The Winterfell Huis Clos


House Frey is surprisingly well represented at the Winterfell wedding: Hosteen and Aenys, Little Walder and Big Walder, the mistress of the castle Walda. Even Symond, Rhaegar and Jared were supposed to attend, before they were... lost. And a host of two thousand men has been brought along.

Despite this numerous representation, no one saw fit to hang the sigil of the Twins among the banners of the high lords who honored the wedding by their presence.

The Frey family is now among the most despised in the Seven Kingdoms, for the transgression of the Red Wedding.

The population of GRRM's world is characterized by fragmentation. No human category is homogeneous, especially not on the moral level, as Val explained eloquently to Jon Snow.
“Free folk and kneelers are more alike than not, Jon Snow. Men are men and women women, no matter which side of the Wall we were born on. Good men and bad, heroes and villains, men of honor, liars, cravens, brutes ... we have plenty, as do you.”
(Jon V, ADwD)

Ned Stark is not representative of his kin. The Lannister twins who appeared equally wicked to us initially turned out to be quite different on close examination. Whatever its familial or ethnic background, any soul deserves its moral evaluation on its own terms. It seems self-evident to a modern reader, but fantasy literature often seems to deviate from this principle and is often criticized for this fault.

In GRRM's world categorical thinking seems often to be a mistake, recalling perhaps another moral law.

It is immoral to see the Freys uniformly as vermins to be exterminated. It also deprives ourselves of the opportunity to examine the consequences of overpopulation for a noble family, and the delightful particularities of the internal politics of the Frey family. The understanding of the Frey motives is not as simple as it seems and requires some attention.


  1. The Wards of Winterfell
  2. The Squires of the Dreadfort
  3. Walda and the Bolton Inheritance Problem
  4. Aenys and Hosteen
  5. The Frey Endgame and Robb's Will
  6. Lame Lothar and Big Walder's Ambition
  7. Little Walder's Murder

1. The Wards of Winterfell

Let's review the Walders in Winterfell. The sending of both Walders as wards to Winterfell is part of a pact between Robb Stark and the Lord of the Crossing. We first hear of them through Lord Walder.
I proposed that Lord and Lady Arryn foster two of my grandsons at court, and offered to take their own son to ward here at the Twins. Are my grandsons unworthy to be seen at the king’s court? They are sweet boys, quiet and mannerly. Walder is Merrett’s son, named after me, and the other one... heh, I don’t recall... he might have been another Walder, they’re always naming them Walder so I’ll favor them, but his father... which one was his father now?
(Catelyn VII, AGoT)

So the project of fostering away the Walders has not begun with the Starks. Why those two boys? Were they the only gransons of Lord Walder of the appropriate age? Visibly Big Walder was not the personal choice of Lord Walder for the fostering.

Little Walder is the larger one, in weight and height. But Big Walder is the older one, by fifty two days.

Little Walder is Merrett Frey and Mariya Darry's son, and Walder Frey's grandson, by his fourth wife, Amarei Crakehall. He is also Fat Walda's brother, and Roose's brother in law. He is also Hosteen's nephew, and Symond's nephew.

It is understandable that every Frey keeps track of his mother on his banner to differentiate himself from cousins and half-siblings. Hence the banners of the Walders.
Little Walder quartered the twin towers of Frey with the brindled boar of his grandmother’s House and the plowman of his mother’s: Crakehall and Darry, respectively. Big Walder’s quarterings were the tree-and-ravens of House Blackwood and the twining snakes of the Paeges.
(Bran II, ACoK)
One quarter of Little Walder's banner might have earned him an epithet by Theon.
And Little Walder was a piglet.
(Theon, ADwD)
And, in the word of his uncle Hosteen (Theon, ADwD)
“Butchered like a hog and shoved beneath a snowbank. A boy.”

Little Walder is very aware that he has no chance to rule the twins, and therefore needs to find his life elsewhere, while Big Walder has ambitions.
Little Walder objected. “And neither of us will ever hold the Twins, stupid.”
“I will,” Big Walder declared.
(Bran I, ACoK)
We will return to Big Walder's ambitions. The Walders become friends with Rickon.
After that, oddly, Rickon decided he liked the Walders. They never played lord of the crossing again, but they played other games-monsters and maidens, rats and cats, come-into-my-castle, all sorts of things. With Rickon by their side, the Walders plundered the kitchens for pies and honeycombs, raced round the walls, tossed bones to the pups in the kennels, and trained with wooden swords under Ser Rodrik’s sharp eye. Rickon even showed them the deep vaults under the earth where the stonemason was carving father’s tomb. “You had no right!” Bran screamed at his brother when he heard. “That was our place, a Stark place!” But Rickon never cared.
(Bran I, ACoK)

Consequently, after the Sack of Winterfell, the Walders are among the few people alive with the knowledge of the location of the crypts.

At the Harvest Feast, the Walders are friends with the White Harbor squires (Bran, ACoK)

The Walders would break lances with the squires of Lord Manderly’s escort, but Bran would have no part of it.

and laugh with them at Hodor's expense.
“Now there’s an ugly horse,” he said of Hodor.
“Hodor’s no horse,” Bran said.
“Hodor,” said Hodor.
Big Walder trotted up to join his cousin. “Well, he’s not as smart as a horse, that’s for certain.”
A few of the White Harbor lads poked each other and laughed.
(Bran II, ACoK)
But only Big Walder has regrets.
“We were having a jape with Hodor,” confessed Big Walder. “I am sorry if we offended Prince Bran. We only meant to be amusing.” He at least had the grace to look abashed.
(Bran II, ACoK)
At the high table, Bran is reminded to send the Walders some choice dishes.
Ser Rodrik reminded him to send something to his foster brothers, so he sent Little Walder some boiled beets and Big Walder the buttered turnips.
(Bran III, ACoK)
It would seem Bran likes Big Walder a bit better.

Here is how the Walders reacted to the death of the heir of the Twins, their uncle Stevron.
Maester Luwin turned to the Walders. “My lords, your uncle Ser Stevron Frey was among those who lost their lives at Oxcross. He took a wound in the battle, Robb writes. It was not thought to be serious, but three days later he died in his tent, asleep.”
Big Walder shrugged. “He was very old. Five-and-sixty, I think. Too old for battles. He was always saying he was tired.”
Little Walder hooted. “Tired of waiting for our grandfather to die, you mean. Does this mean Ser Emmon’s the heir now?”
“Don’t be stupid,” his cousin said. “The sons of the first son come before the second son. Ser Ryman is next in line, and then Edwyn and Black Walder and Petyr Pimple. And then Aegon and all his sons.”
“Ryman is old too,” said Little Walder. “Past forty, I bet. And he has a bad belly. Do you think he’ll be lord?”
“I’ll be lord. I don’t care if he is.”
Maester Luwin cut in sharply. “You ought to be ashamed of such talk, my lords. Where is your grief? Your uncle is dead.”
“Yes,” said Little Walder. “We’re very sad.”
(Bran I, ACoK)
When Theon assembled a hunting party to search for Bran, Rickon etc, Little Walder volunteered.
“Let me come too. I want that wolfskin cloak.” A boy stepped forward, no older than Bran. It took Theon a moment to remember him. “I’ve hunted lots of times before,” Walder Frey said. “Red deer and elk, and even boar.”
His cousin laughed at him. “He rode on a boar hunt with his father, but they never let him near the boar.”
(Theon IV, ACoK)
(Note that the boar is on Little Walder's banner as the sigil of the Crakehalls.)

Little Walder came to learn that Theon and "Reek" went to the mill to find Bran and Rickon. So he could be a important witness if there is an inquiry on the death of the young Starks. But he shouldn't know that Bran and Rickon weren't truly executed.

2. The Squires of the Dreadfort

After the sack of Winterfell, the Freys were saved by Ramsay and they were taken at the Dreadfort.

Ramsay asked his men to spare the Freys during the Sack of Winterfell. It's an open question whether he obeyed a command of his father.

In any case the Walders are dangerous for him, since they know that Ramsay sacked Winterfell, and that he impersonated Reek and helped Theon. Little Walder even knows more, as we saw.

The news of the Walders' survival arrived at the Twins and was reported by Lothar Frey.
“Walder and Walder, yes. But they are presently at the Dreadfort, my lady. I grieve to tell you this, but there has been a battle. Winterfell is burned.”
“Burned?” Robb’s voice was incredulous.
“Your northern lords tried to retake it from the ironmen. When Theon Greyjoy saw that his prize was lost, he put the castle to the torch.”
“We have heard naught of any battle,” said Ser Brynden.
“My nephews are young, I grant you, but they were there. Big Walder wrote the letter, though his cousin signed as well. It was a bloody bit of business, by their account. Your castellan was slain. Ser Rodrik, was that his name?”
“Ser Rodrik Cassel,” said Catelyn numbly. That dear brave loyal old soul. She could almost see him, tugging on his fierce white whiskers. “What of our other people?”
“The ironmen put many of them to the sword, I fear.”
Wordless with rage, Robb slammed a fist down on the table and turned his face away, so the Freys would not see his tears.
But his mother saw them. The world grows a little darker every day. Catelyn’s thoughts went to Ser Rodrik’s little daughter Beth, to tireless Maester Luwin and cheerful Septon Chayle, Mikken at the forge, Farlen and Palla in the kennels, Old Nan and simple Hodor. Her heart was sick. “Please, not all.”
“No,” said Lame Lothar. “The women and children hid, my nephews Walder and Walder among them. With Winterfell in ruins, the survivors were carried back to the Dreadfort by this son of Lord Bolton’s.-”
“Bolton’s son?” Robb’s voice was strained.
Walder Rivers spoke up. “A bastard son, I believe.”
“Not Ramsay Snow? Does Lord Roose have another bastard?” Robb scowled. “This Ramsay was a monster and a murderer, and he died a coward. Or so I was told.”
“I cannot speak to that. There is much confusion in any war. Many false reports. All I can tell you is that my nephews claim it was this bastard son of Bolton’s who saved the women of Winterfell, and the little ones. They are safe at the Dreadfort now, all those who remain.”
“Theon,” Robb said suddenly. “What happened to Theon Greyjoy? Was he slain?”
Lame Lothar spread his hands. “That I cannot say, Your Grace. Walder and Walder made no mention of his fate. Perhaps Lord Bolton might know, if he has had word from this son of his.”
Ser Brynden said, “We will be certain to ask him.”
“You are all distraught, I see. I am sorry to have brought you such fresh grief. Perhaps we should adjourn until the morrow. Our business can wait until you have composed yourselves...”
(Catelyn IV, ASoS)

We will return to Lothar. It's likely that the Walders lied under threat. And Big Walder was the most willing of the two it seems. Of course the letter is also a testimony of the survival of the Walders, and the proof that Ramsay has hostages.

Indeed, the Walders are mentioned at the Red Wedding.
Bolton had made a toast to Lord Walder’s grandsons when the wedding feast began, pointedly mentioning that Walder and Walder were in the care of his bastard son. From the way the old man had squinted at him, his mouth sucking at the air, Catelyn knew he had heard the unspoken threat.
(Catelyn VII, ASoS)

Both Walders became Ramsay's squire. Both Walders were sent to take Theon from the dungeons and bring him to the Dreadfort feast.

Wyman Manderly has agreed to marry his granddaughter Wylla to Little Walder, as Rhaegar tells her.
“Lady Wylla,” he said to the girl with the green braid, “loyalty is a virtue. I hope you will be as loyal to Little Walder when you are joined in wedlock.
(Davos III, ADwD)

Here again, Little Walder seems preferred to his cousin, and he is the one for whom a marriage has been arranged. A marriage to a boy fostered at the Dreadfort is also a mean to increase the power of the Boltons at White Harbor.

The Walders get along with Ramsay's boys and Whoresbane at Moat Cailin.
Whoresbane was with him, along with half a dozen of his favorites, Skinner and Sour Alyn and Damon Dance-for-Me, and the Walders Big and Little too.
(Reek II, ADwD)

They are part of the hunting party led by Ramsay to search for the three Freys that were lost on their way from White Harbor.
Outside, beneath a cold autumnal sky, the hunters were pouring through the gates. Ben Bones led the way, with the girls baying and barking all around him. Behind came Skinner, Sour Alyn, and Damon Dance-for-Me with his long greased whip, then the Walders riding the grey colts Lady Dustin had given them. His lordship himself rode Blood, a red stallion with a temper to match his own.
(Reek III, ADwD)

Note the special attention Barbrey Dustin has given them. The grey colts reminds me of the guest gift, three palfreys, Manderly has presented to the other Freys before their departure. Lady Dustin never seems fond of the Freys in general. Did Lady Dustin try to be friends with the Walders so that they would report on Ramsay to her?

Theon takes note of the differences between the Walders.
Little Walder had become Lord Ramsay’s best boy and grew more like him every day, but the smaller Frey was made of different stuff and seldom took part in his cousin’s games and cruelties.
(Reek III, ADwD)
It seems that Little Walder is very much his father's son. Here is how Jaime recalls Merrett Frey:
“We were squires together once, at Crakehall.” He would not go so far as to claim they had been friends. When Jaime had arrived, Merrett Frey had been the castle bully, lording it over all the younger boys. Then he tried to bully me. “He was . . . very strong.” It was the only praise that came to mind. Merrett had been slow and clumsy and stupid, but he was strong.
(Jaime IV, AFfC)
When Theon asks Big Walder about the search undertaken by Ramsay and his boys.
“Did you find your cousins, my lord?”
“No. I never thought we would. They’re dead. Lord Wyman had them killed. That’s what I would have done if I was him.”
(Reek III, ADwD)

Big Walder comes out as a thoughtful, ambitious, independent-minded boy. But Little Walder is Ramsay's favorite.
It fell to Little Walder to keep Lord Ramsay’s cup filled, whilst Big Walder poured for the others at the high table.
(Reek III, ADwD)
Let's end the review with little details. At the Wedding Feast, Little Walder dances with the washerwomen.
Another one had pulled Little Walder Frey up onto the table to teach him how to dance.
(The Prince of Winterfell, ADwD)
Little Walder is among the squires who have made snowmen in Winterfell.
He might have taken the guards for a pair of Little Walder’s snowmen if he had not seen the white plumes of their breath.
(A Ghost in Winterfell, ADwD)
Now we turn to important matter.

3. Walda and the Bolton inheritance problem

Let's have a short look at Walda Frey, daughter of Merrett Frey and Mariya Darry, granddaughter of Lord Walder and Amerei Crakehall.

We first hear of her through Edmure Tully, when Catelyn returns to her visit to Renly's court.
Robb’s betrothed to one of Lord Walder’s daughters, and Roose Bolton wed another, I hear.
(Catelyn V, ACoK)

It seems Roose married Walda after he lost the battle of the Green Fork, and before he marched on Harrenhal.

At the Red Wedding, she does not appear to be a character of much consequence.
“Everyone thought my lord would choose Fair Walda,” Lady Walda Bolton told Ser Wendel, shouting to be heard above the music. Fat Walda was a round pink butterball of a girl with watery blue eyes, limp yellow hair, and a huge bosom, yet her voice was a fluttering squeak. It was hard to picture her in the Dreadfort in her pink lace and cape of vair. “My lord grandfather offered Roose his bride’s weight in silver as a dowry, though, so my lord of Bolton picked me.” The girl’s chins jiggled when she laughed. “I weigh six stone more than Fair Walda, but that was the first time I was glad of it. I’m Lady Bolton now and my cousin’s still a maid, and she’ll be nineteen soon, poor thing.”
(Catelyn VII, ASoS)
Indeed, the marriage is generally considered a surprise.
“Fortunately for you, I have no need of a wife. I wed the Lady Walda Frey whilst I was at the Twins.”
“Fair Walda?” Awkwardly, Jaime tried to hold the bread with his stump while tearing it with his left hand.
“Fat Walda. My lord of Frey offered me my bride’s weight in silver for a dowry, so I chose accordingly. Elmar, break off some bread for Ser Jaime.”
(Jaime V, ASoS)

It is interesting to note the competition between Fair Walda and Fat Walda for Roose's hand. Fat Walda is a Crakehall Frey while Fair Walda is a Royce Frey. The Crakehall Freys and the Royce Freys are probably the two most numerous and most powerful factions at the Twins. The Crakehall Freys got the seat of Darry already, while the Royce Freys will inherit the Twins, as well as Riverrun. Surely Roose has considered all that before marrying his preferred Walda.

The Freys and Ramsay are not natural allies. They are competing for Roose's inheritance. Indeed, Fat Walda is Little Walder's sister, and Hosteen Frey's nephew. She wrote Roose:
I pray for you morn, noon, and night, my sweet lord,” she wrote, “and count the days until you share my bed again. Return to me soon, and I will give you many trueborn sons to take the place of your dear Domeric and rule the Dreadfort after you.
(Arya X, ACoK)

So there is no doubt about Walda's intention to give birth to the next Lord of the Dreadfort. In Harrenhal, Roose does not pay the least attention to Walda's letters. He orders Arya:
“And tend to Lady Walda’s letter.”
“As you say, my lord.”
The lord and maester swept from the room, giving her not so much as a backward glance. When they were gone, Arya took the letter and carried it to the hearth, stirring the logs with a poker to wake the flames anew. She watched the parchment twist, blacken, and flare up.
(Arya X, ACoK)
Roose had written for all the north to read, and even a few Freys, when Ramsay was thought dead, that:
“A fate he no doubt earned,” Bolton had written. “Tainted blood is ever treacherous, and Ramsay’s nature was sly, greedy, and cruel. I count myself well rid of him. The trueborn sons my young wife has promised me would never have been safe while he lived.”
(Catelyn VI, ACoK)

In effect that is an announce that Ramsay would kill his sons by Walda. It must have proved embarrassing when Ramsay reappeared. When asked, Roose makes a diplomatic statement.
“Your bastard was accused of grievous crimes,” Catelyn reminded him sharply. “Of murder, rape, and worse.”
“Yes,” Roose Bolton said. “His blood is tainted, that cannot be denied. Yet he is a good fighter, as cunning as he is fearless. When the ironmen cut down Ser Rodrik, and Leobald Tallhart soon after, it fell to Ramsay to lead the battle, and he did. He swears that he shall not sheathe his sword so long as a single Greyjoy remains in the north. Perhaps such service might atone in some small measure for whatever crimes his bastard blood has led him to commit.” He shrugged. “Or not. When the war is done, His Grace must weigh and judge. By then I hope to have a trueborn son by Lady Walda.”
(Catelyn VI, ASoS)
Indeed, Walda is present at the Red Wedding.
His heart should be well pleased, then; Robb had done his duty like a king. He had danced with each of the girls, with Edmure’s bride and the eighth Lady Frey, with the widow Ami and Roose Bolton’s wife Fat Walda, with the pimply twins Serra and Sarra, even with Shirei, Lord Walder’s youngest, who must have been all of six.
(Catelyn VII, ASoS)

We don't know if she played an active part in the massacre. But she was surprisingly lighthearted, and not frightened like Roslin. Here she is about Edmure's one-eyed fish.
“Nay, I’ll wager it’s a minnow,” Fat Walda Bolton shouted out from Catelyn’s side.
(Catelyn VII, ASoS)
She doesn't seem very much appreciated by old lord Walder.
Merrett had dared to hope that his luck was finally changing when Roose Bolton chose to wed his Walda instead of one of her slimmer, comelier cousins. The Bolton alliance was important for House Frey and his daughter had helped secure it; he thought that must surely count for something. The old man had soon disabused him. “He picked her because she’s fat,” Lord Walder said. “You think Bolton gave a mummer’s fart that she was your whelp? Think he sat about thinking, ‘Heh, Merrett Muttonhead, that’s the very man I need for a good-father’? Your Walda’s a sow in silk, that’s why he picked her, and I’m not like to thank you for it. We’d have had the same alliance at half the price if your little porkling put down her spoon from time to time.”
(Epilogue, ASoS)

The stage has been set for a confrontation between the Freys and Ramsay. Indeed, Roose told Theon one of the strangest utterances I found in the books.
“And won’t my bastard love that? Lady Walda is a Frey, and she has a fertile feel to her. I have become oddly fond of my fat little wife. The two before her never made a sound in bed, but this one squeals and shudders. I find that quite endearing. If she pops out sons the way she pops in tarts, the Dreadfort will soon be overrun with Boltons. Ramsay will kill them all, of course. That’s for the best. I will not live long enough to see new sons to manhood, and boy lords are the bane of any House. Walda will grieve to see them die, though.”
(Reek III, ADwD)

I do not know whether anyone besides Theon heard Roose's prediction that Ramsay will kill Fat Walda's children. However, such words are the seeds of hate between the Freys (especially those close to Fat Walda) and Ramsay. The passage will be discussed as part of the analysis of Roose.

But note that just before this exchange, Roose has confided to Theon.
“Yes, m’lord. Domeric. I ... I have heard his name ...”
“Ramsay killed him. […] Tell me, my lord ... if the kinslayer is accursed, what is a father to do when one son slays another?”
The question frightened him. Once he had heard Skinner say that the Bastard had killed his trueborn brother, but he had never dared to believe it.
(Reek III, ADwD)
I suppose the Walders have heard the same thing, since they hang out with Ramsay and the Bastard's boys. 

Here is the Freys' expectation for Ramsay, from Rhaegar Frey's mouth at the Merman's court.
“Lady Wylla,” he said to the girl with the green braid, “loyalty is a virtue. I hope you will be as loyal to Little Walder when you are joined in wedlock. As to the Starks, that House is extinguished only in the male line. Lord Eddard’s sons are dead, but his daughters live, and the younger girl is coming north to wed brave Ramsay Bolton.”
“Ramsay Snow,” Wylla Manderly threw back. “Have it as you will. By any name, he shall soon be wed to Arya Stark. If you would keep faith with your promise, give him your allegiance, for he shall be your Lord of Winterfell.”
“He won’t ever be my lord! He made Lady Hornwood marry him, then shut her in a dungeon and made her eat her fingers.”
A murmur of assent swept the Merman’s Court. “The maid tells it true,” declared a stocky man in white and purple, whose cloak was fastened with a pair of crossed bronze keys. “Roose Bolton’s cold and cunning, aye, but a man can deal with Roose. We’ve all known worse. But this bastard son of his ... they say he’s mad and cruel, a monster.”
“They say?” Rhaegar Frey sported a silky beard and a sardonic smile. “His enemies say, aye ...
(Davos III, ADwD)

So the Freys think Ramsay will be Lord of Winterfell so that Walda and her children can have the Dreadfort.

Note that words fail Rhaegar when he has to defend Ramsay. Indeed, he changes the subject to rant on the Young Wolf.

At the wedding, here is Ramsay's claim.
“Ramsay of House Bolton, Lord of the Hornwood, heir to the Dreadfort. I claim her. Who gives her?
(The Prince of Winterfell, ADwD)

Ramsay is not interested in Winterfell and wants to remain heir to the Dreadfort. This will be further discussed as part of the analysis of Ramsay.

Just before the escape Fat Walda is noticed to be pregnant.
Roose Bolton entered, pale-eyed and yawning, accompanied by his plump and pregnant wife, Fat Walda.
(Theon , ADwD)

So there is no further escape from the problem. When the child will be born, Roose will have to decide who is the heir.

Little Walder's loyalty has to be split between Ramsay and his family, by extension Roose. Little Walder is a young boy, and might not fully comprehend those questions. However, I wouldn't be surprised if both Little Walder and Big Walder had been told to report to their family what they would see while being fostered at Winterfell.

Given that Little Walder seemed to enjoy his time with Ramsay, it's an open question to determine where Little Walder's loyalties lied when he reunited with his family (his sister Walda, his uncle Hosteen in particular) in Moat Cailin.

When the Walders wrote to the Twins from the Dreadfort, they seemed intent on covering Ramsay's lies.
“This Ramsay was a monster and a murderer, and he died a coward. Or so I was told.”
“I cannot speak to that. There is much confusion in any war. Many false reports. All I can tell you is that my nephews claim it was this bastard son of Bolton’s who saved the women of Winterfell, and the little ones. They are safe at the Dreadfort now, all those who remain.”
“Theon,” Robb said suddenly. “What happened to Theon Greyjoy? Was he slain?”
Lame Lothar spread his hands. “That I cannot say, Your Grace. Walder and Walder made no mention of his fate. Perhaps Lord Bolton might know, if he has had word from this son of his.”
(Catelyn IV, ASoS)

In all likehood, when they joined in Moat Cailin Little Walder was asked about Ramsay by Hosteen Frey and Walda. It's doubtful that he refrained from saying that Ramsay was in Winterfell and helped murder "Bran" and "Rickon". From that point, there must be immense tension between the Freys and Ramsay. Big Walder might have been asked as well. He does not seem very close to Ramsay. It's unlikely that both Walders kept the secret.

The Freys were probably tempted to use both Walders as spies on Ramsay. Moreover, Little Walder is in charge of filling Ramsay's cup, and is ideally placed to poison him, or so could think Ramsay.

I wonder if the real reason the Freys came with so many troops to the wedding wasn't to insure the safety of Walda.

If I were Walda, I would make sure to be on good terms with Walton Steelshanks, who seems to hold the most authority over the men of the Dreadfort. In case Roose dies prematurely, Walton could be the one who would decide whether Walda or Ramsay would rule over the Dreadfort.

4. Aenys and Hosteen

Here is the Frey host passing Moat Cailin.
Three days later, the vanguard of Roose Bolton’s host threaded its way through the ruins and past the row of grisly sentinels—four hundred mounted Freys clad in blue and grey, their spearpoints glittering whenever the sun broke through the clouds. Two of old Lord Walder’s sons led the van. One was brawny, with a massive jut of jaw and arms thick with muscle. The other had hungry eyes close-set above a pointed nose, a thin brown beard that did not quite conceal the weak chin beneath it, a bald head. Hosteen and Aenys. He remembered them from before he knew his name. Hosteen was a bull, slow to anger but implacable once roused, and by repute the fiercest fighter of Lord Walder’s get. Aenys was older, crueler, and more clever—a commander, not a swordsman. Both were seasoned soldiers.


And at the rear, more Freys. At least a thousand, maybe more: bowmen, spearmen, peasants armed with scythes and sharpened sticks, freeriders and mounted archers, and another hundred knights to stiffen them.
(Reek II, ADwD)
We have another description of the Freys' forces from Cersei Lannister.
“Not for long. Bolton’s bastard son will soon remove that little obstacle. Lord Bolton will have two thousand Freys to augment his own strength, under Lord Walder’s sons Hosteen and Aenys. That should be more than enough to deal with Stannis and a few thousand broken men.”
(Jaime II, AFfC)
It's interesting to see what the Freys' van saw when it arrived in the north.
The next morning Lord Ramsay dispatched three riders down the causeway to take word to his lord father that the way was clear. The flayed man of House Bolton was hoisted above the Gatehouse Tower, where Reek had hauled down the golden kraken of Pyke. Along the rotting-plank road, wooden stakes were driven deep into the boggy ground; there the corpses festered, red and dripping. Sixty-three, he knew, there are sixty-three of them. One was short half an arm. Another had a parchment shoved between its teeth, its wax seal still unbroken.
Three days later, the vanguard of Roose Bolton’s host threaded its way through the ruins and past the row of grisly sentinels—four hundred mounted Freys clad in blue and grey, their spearpoints glittering whenever the sun broke through the clouds. Two of old Lord Walder’s sons led the van.
(Reek II, ADwD)

The Frey army appears to be the first southern army ever to come to the north. One could understand the flayed ironborn as a warning to southerner.

The Freys are led by Hosteen Frey and Aenys Frey.

Aenys is the older of the two, the third son of Walder Frey by his first wife, Perra Royce. He is far in the order of succession, since his older brothers Stevron and Emmon have amply enough descendants. He is the first son of Walder Frey without a secure position, it seems (Emmon is lord of Riverrun). His sons have been given Targaryen names (Aegon, Rhaegar). Aegon has become an outlaw, and is probably not part of Aenys' plans. The other son Rhaegar was promised to Wynafrei Manderly, herself eldest daughter of Wylis Manderly. So Rhaegar could hope to become Lord of White Harbor, securing thus a place for Aenys and his descendants. However, Rhaegar's sons from his previous marriage, Robert and Jonos, would not inherit anything and do not have any position secured. But Rhaegar is, we presume, dead and eaten by the guests at Winterfell.

Aenys Frey seems to be trusted as a military commander, he was already with Roose Bolton in Harrenhal. It would seem that he is one of the more important Freys. The fact that the heir of the Twins will be descended from Perra Royce might help his situation when Lord Walder passes away. But it seems to me that Aenys has come in the north with the Frey army to find a seat for himself, or his grandsons and to secure the position of Rhaegar in White Harbor.

The situation of Hosteen is different. He is born from Lord Walder's third wife, Amarei Crakehall. Like many Crakehall, he is physically strong. Hosteen is the uncle of Walda Frey, and, since Merrett Frey has been hung by the Brotherhood, he might be something like a father figure for Walda, possibly appearing as her defender in the rivalry with Ramsay. There is an allusion to the closeness of Hosteen and Merrett in the lamentation at the death of Little Walder.
“My brother Merrett’s son.” Hosteen Frey lowered the body to the floor before the dais. “Butchered like a hog and shoved beneath a snowbank. A boy.”
(Theon, ADwD)

So, the close families ties entertained by Walda, Little Walder and Hosteen have to be kept in mind, especially since most Freys dread the day of the death of Lord Walder. Here is Merrett.
It was like to be every son for himself when the old man died, and every daughter as well. The new Lord of the Crossing would doubtless keep on some of his uncles, nephews, and cousins at the Twins, the ones he happened to like or trust, or more likely the ones he thought would prove useful to him. The rest of us he’ll shove out to fend for ourselves.
(Epilogue, ASoS)

Hosteen is in a better position than Merrett. He might hope that Walda would keep him at her side at the Dreadfort. In any case, Merrett's other daughter Amarei is now Lady of Darry, and Merrett's widow Mariya and Hosteen's eldest son Arwood are with her, and could hope to take over the seat, since Amarei's husband, Lancel Lannister, is losing interest in the Lordship.

Barbrey Dustin thinks Roose could claim the title of King of the North, and the Freys might think as much. So for Hosteen, securing Walda's situation is possibly more important than the mission of pacification of the north that the Lannisters have assigned to the Freys.

The army led by Aenys and Hosteen that came from the twins is considerable, larger than any northern lord's, except Roose Bolton's. Note the large number of mounted men (five hundred). It seems stronger than the Manderly host (three hundred men, including a hundred knights).

Hosteen has one misfortune in Winterfell
No less a man than Hosteen Frey, who had been heard growling that he did not fear a little snow, lost an ear to frostbite.
(A Ghost in Winterfell, ADwD)

Does this mean that Hosteen had been busy outside while all guests at the wedding were keeping themselves warm near the fire?

A few words on Rhaegar, Jared and Symond. They came to White Harbor with their family. Lord Wyman complains of them.
They watch me, ser. Day and night their eyes are on me, noses sniffing for some whiff of treachery. You saw them, the arrogant Ser Jared and his nephew Rhaegar, that smirking worm who wears a dragon’s name. Behind them both stands Symond, clinking coins. That one has bought and paid for several of my servants and two of my knights. One of his wife’s handmaids has found her way into the bed of my own fool.
(Davos IV, ADwD)

What did the family of those Freys become? Did they remain in White Harbor? Are they kept prisoner somewhere? Symond was Hosteen's brother, Rhaegar was Aenys' son, and Jared was Lord Walder's son by his second wife, a Swann. They are descended from the first three wives of Lord Walder.

It seems that Symond was married to a Braavosi (Bethario of Braavos). Since Symond was the treasurer and spymaster at the Twins, I find interesting that he married a Braavosi. Is Bethario related to the financial institutions of Braavos? Does Symond's competence as a spymaster come from Bethario? Their second son Bradamar is fostered by a merchant named Oros Tendyris. It lets us presume that Tendyris is a relative of Bethario, her father, her brother, her uncle etc.

5. The Frey Endgame and Robb's Will

So many Freys risk finding themselves impoverished after old Walder's demise that such a perspective is creating enormous tensions at the Twins. It's a vital necessity to find a solution to the overpopulation.

Given this situation, the strategy of the Freys with the Red Wedding has been to acquire seats and lands in the north. And in the south, too. Witness how many Freys are to be found at Darry, since the seat has been given to Lancel Lannister and his wife Amerei Frey.
“You must forgive my daughter,” said an older woman. Lady Amerei had brought a score of Freys to Darry with her; a sister, an uncle, a half uncle, various cousins . . . and her mother, who had been born a Darry.
(Jaime, AFfC)

Amerei is Walda's and Little Walder's sister, Merrett 's daughter, and Hosteen Frey's nephew. I understand from this that the Crakehall Freys have a certain attachment to family ties, especially Merrett and Hosteen's children.

Of course, Emmon Frey, Lord Walder's second son, has been given Riverrun, in reason of his marriage to Genna Lannister. So the Freys control three major seats in the south. And Roslin Frey is married to Edmure Tully and pregnant.

In the north, the cornerstone of the Frey plan is the marriage of Walda and Roose. Thus a son of Roose and Walda will inherit the dominant seat in the north. Other marriages have been arranged. (Little Walder with Wylla Manderly and Rhaegar Frey and Wynafrei Manderly.) It is to be expected that Roose will find himself surrounded by Freys asking for lands, favors and spouses, just like Stannis is harassed by Massey, Thorpe etc for northern brides.

In a sense that resembles what happened when the Andals came to Westeros. The lands that couldn't be obtained from the First Men by conquest were gained through marriage.

In the perspective of dominating the north, Ramsay is a rival to the Freys' ambitions.

The Freys and Roose do not trust each other very much. Here is Roose at the Red Wedding.
Bolton had made a toast to Lord Walder’s grandsons when the wedding feast began, pointedly mentioning that Walder and Walder were in the care of his bastard son. From the way the old man had squinted at him, his mouth sucking at the air, Catelyn knew he had heard the unspoken threat.
(Catelyn VII, ASoS)

We are left to wonder whether the marriage to Walda means much for Roose. It seems that the Freys need Roose more than Roose needs the Frey now. And the Freys are in need of a mean of influence on the Boltons.

It might be that one providentially fell into their hands.

In view of the apparent demise of Arya, Bran and Rickon, and in view of the marriage of Sansa to a Lannister, it seems that Robb Stark named Jon Snow his heir, as king of the north.
“No,” Catelyn agreed. “You must name another heir, until such time as Jeyne gives you a son.” She considered a moment. “Your father’s father had no siblings, but his father had a sister who married a younger son of Lord Raymar Royce, of the junior branch. They had three daughters, all of whom wed Vale lordlings. A Waynwood and a Corbray, for certain. The youngest... it might have been a Templeton, but...”
“Mother.” There was a sharpness in Robb’s tone. “You forget. My father had four sons.”
She had not forgotten; she had not wanted to look at it, yet there it was. “A Snow is not a Stark.”
“Jon’s more a Stark than some lordlings from the Vale who have never so much as set eyes on Winterfell.”
“If Jon is a brother of the Night’s Watch, sworn to take no wife and hold no lands. Those who take the black serve for life.”
“So do the knights of the Kingsguard. That did not stop the Lannisters from stripping the white cloaks from Ser Barristan Selmy and Ser Boros Blount when they had no more use for them. If I send the Watch a hundred men in Jon’s place, I’ll wager they find some way to release him from his vows.”
He is set on this. Catelyn knew how stubborn her son could be. “A bastard cannot inherit.”
“Not unless he’s legitimized by a royal decree,” said Robb. “There is more precedent for that than for releasing a Sworn Brother from his oath.”
“Precedent,” she said bitterly. “Yes, Aegon the Fourth legitimized all his bastards on his deathbed. And how much pain, grief, war, and murder grew from that? I know you trust Jon. But can you trust his sons? Or their sons? The Blackfyre pretenders troubled the Targaryens for five generations, until Barristan the Bold slew the last of them on the Stepstones. If you make Jon
legitimate, there is no way to turn him bastard again. Should he wed and breed, any sons you may have by Jeyne will never be safe.”
“Jon would never harm a son of mine.”
“No more than Theon Greyjoy would harm Bran or Rickon?”
Grey Wind leapt up atop King Tristifer’s crypt, his teeth bared. Robb’s own face was cold.
“That is as cruel as it is unfair. Jon is no Theon.”
“So you pray. Have you considered your sisters? What of their rights? I agree that the north must not be permitted to pass to the imp, but what of Arya? By law, she comes after Sansa... your own sister, trueborn...”
“... and dead. No one has seen or heard of Arya since they cut Father’s head off. Why do you lie to yourself? Arya’s gone, the same as Bran and Rickon, and they’ll kill Sansa too once the dwarf gets a child from her. Jon is the only brother that remains to me. Should I die without issue, I want him to succeed me as King in the North. I had hoped you would support my choice.”
“I cannot,” she said. “In all else, Robb. In everything. But not in this... this folly. Do not ask it.”
“I don’t have to. I’m the king.”
(Catelyn V, ASoS)
A bit later, a document has been prepared witnessed by a number of northmen apposing their signature.
“One more matter. Lord Balon has left chaos in his wake, we hope. I would not do the same. Yet I have no son as yet, my brothers Bran and Rickon are dead, and my sister is wed to a Lannister. I’ve thought long and hard about who might follow me. I command you now as my true and loyal lords to fix your seals to this document as witnesses to my decision.”
(Catelyn V, ASoS)

Here are the lords in attendance: Jason Mallister, Galbart Glover, Maege Mormont, Greatjon Umber, Edmure Tully.

There were a few more highborn northmen: Wendel Manderly, Robin Flint, Donnel Locke, Lucas Blackwood, Raynald Westerling, Marq Piper, Lymond Goodbrook, young Vances. 

It is not known where the document is. I see three possibilities: with Galbart Glover and Maege Mormont, with Jason Mallister in Seaguard, brought at the Twins.

There is little reason for the King not to have kept the document with him. And certainly little reason to have given it to Glover and Mormont who are about to undertake an uncertain mission with the crannogmen. Glover and Mormont were not sent to proclaim the content of the will since they were intent of rallying Howland Reed for the battle of Moat Cailin. The second option is more reasonable, but we are given no indication of that.

So, the third option is the most likely. In that case, either Roose Bolton or the Freys could have found the parchment.

Roose would certainly have destroyed the will if he had put his hands on it. But it seems more likely that the Freys found it, and kept it to themselves as a trump card. Indeed, we don't know if Jon is named crown prince of the north, or simply heir of Winterfell, or if there are certain provisions concerning the survival of Arya, Bran and Rickon. But, whatever the wording, the Freys would be in position to blackmail the Boltons, since the publication of the will would undermine the legitimacy of Roose as Lord Paramount of the north, and would deprive "Arya" of Winterfell. Even if the will states that the crown of the north should go to Jon, it doesn't deprive Walda of the Dreadfort. It would just make the Boltons bannermen of the Stark again. And Ramsay would lose Winterfell.

Of course the will doesn't mean much unless it is backed by significant forces. It could be treated just like Robert Baratheon's last will has been by his widow. It could be interpreted in various ways depending on the political circumstances, including that Jon would inherit the lordship of Winterfell, but not the crown.

Even if the will appears for all the north to see and is not accepted, it will pose the problem of the place of legitimized bastards in the order for inheritance. If Jon Snow is discarded for the lordship of Winterfell, so must Ramsay for the lordship of the Dreadfort. It is worthwhile to reflect on Robett Glover's words on Ramsay.
“He is a bastard born of rape. A Snow, no matter what the boy king says.”
(Davos, ADwD)

I would presume that the Freys would demand from Roose that Walda's son would inherit the Dreadfort in exchange for their silence on Robb's will.

In any case, the Freys are in need of political weapons in the north. They depend too much on Roose's goodwill. Lady dustin has threatened them in the name of all the north.
“And Lord Wyman is not the only man who lost kin at your Red Wedding, Frey. Do you imagine Whoresbane loves you any better? If you did not hold the Greatjon, he would pull out your entrails and make you eat them, as Lady Hornwood ate her fingers. Flints, Cerwyns, Tallharts, Slates ... they all had men with the Young Wolf.”
“House Ryswell too,” said Roger Ryswell. “Even Dustins out of Barrowton.” Lady Dustin parted her lips in a thin, feral smile. “The north remembers, Frey.”
Aenys Frey’s mouth quivered with outrage. “Stark dishonored us. That is what you northmen had best remember.”
(A Ghost in Winterfell, ADwD)

Note that Lady Dustin's threat comes after she had made a point of showing Ramsay's cruelty, first by forcing Theon to show his maimed fingers, and then by recalling what happened to Lady Hornwood.

So the Frey know they are not welcome in the north. They are in need of political advantages to ensure Roose's support and calm the hostility of northmen. Here are their strengths.

6. Lothar and Big Walder's ambition

One day Big Walder will rule the Twins. Or so he says. And nobody takes him seriously. Let's examine his perspective.

Big Walder is the son of Jammos Frey, himself the second son of Lord Walder's fourth wife Alyssa Blackwood, and Lord Walder's thirteen's son. The first son of Alyssa is Lame Lothar, steward at the Twins, and mastermind of the Red Wedding with Roose Bolton.

Lothar has four daughters. It is not clear what is the inheritance rule for the Freys. It's certain that girls count for little for Lord Walder.
That wife of mine will give me a son before this time next year, I’ll wager. Or a daughter, that can’t be helped.
(Catelyn VII, AGoT)

It seems the Freys use the agnatic succession issued from the salic law: inheritance is patrilineal. In particular a brother or a son of a brother comes before a daughter. We learn about the inheritance order in the Twins through the Walders. Big Walder corrects his cousin's understanding.
“Don’t be stupid,” his cousin said. “The sons of the first son come before the second son. Ser Ryman is next in line, and then Edwyn and Black Walder and Petyr Pimple. And then Aegon and all his sons.”
(Bran I, ACoK)

Both Edwyn and Petyr have a daughter that should inherit before Aegon. The prevalence of the salic law is confirmed by Edwyn Frey.
Edwyn’s mouth twisted. “My brother had a hand in this, I’ll wager. He allowed the outlaws to escape after they murdered Merrett and Petyr, and this is why. With our father dead, there’s only me left between Black Walder and the Twins.”
(Jaime VII, AFfC)

If the agnatic succession system prevails, Lothar's heir is his brother Jammos, followed by Big Walder, at least as long as Lothar doesn't father a son. In any case, Big Walder and Lothar are both descended from Alyssa Blackwood.

Cersei gives us an hint of what will happen after the demise of Lord Walder.
“Lord Walder will never sacrifice his own,” said Pycelle.
“No,” mused Cersei, “but his heirs may be less squeamish. Lord Walder will soon do us the courtesy of dying, we can hope. What better way for the new Lord of the Crossing to rid himself of inconvenient half brothers, disagreeable cousins, and scheming sisters than by naming them the culprits?”
(Cersei IV, AFfC)

Lothar's situation is interesting. Indeed, the Twins should be inherited by the descendants of Stevron Frey, Lord Walder's first son. Currently Edwyn is the heir, followed by Black Walder. Emmon Frey, Walder's second's son, is Lord of Riverrun. Aenys Frey, Walder's third son, has arranged that his son Rhaegar would marry Wynafrei Manderly, so that their children would inherit White Harbor. So the position of all three sons has been secured.

Jared Frey is Lord Walder's fourth son, by the second Lady Frey, Cyrella Swann. It was never spelled out what the Freys had in mind for him. Probably something in the north, since he was sent at White Harbor, with Rhaegar and Symond, and Rhaegar was promised White Harbor. But Jared is no more, and he has no descendant in the male line except Zachery Frey, who is studying at the Citadel. Septon Luceon is Lord Walder's fifth son, but, in quality of man of the Faith, doesn't count for the inheritance.

Next come the sons born of the third Lady Frey, Amerei Crakehall. I count Hosteen, Symond (presumed dead), Danwell, Merrett (dead), Geremy (dead), Raymund.

Taken together, the sons of the first and third marriages of Lord Walder have so many living descendants in the male line that I stopped counting at around twenty-three. Then comes Lothar. Then comes Big Walder's father Jammos. Then comes Big Walder.

Almost none of the sons of Walder Frey who came before Lothar are in need of a position. Aenys could hope to settle at White Harbor with his son Rhaegar. Being Crakehall Freys, Hosteen, Danwell and Raymund can hope to find shelter at Darry, or at the Dreadfort, or they can hope that Hosteen's current campaign in the north would open new opportunities.

There are no children of Walder Frey by his fifth wife, Lady Whent. The children by the sixth wife, Bethany Rosby, stayed away from the Red Wedding – except obviously Roslin who seems to have been forced. The children of the seventh wife, Annara Farring, are a bit too young, but her eldest daughter, Arwyn was present at the Red Wedding. The eighth wife, Joyeuse Erenford is still childless.

Despite being far in the line of succession, Lothar is in a key position at the Twins, in quality of steward. I suppose his intelligence and his glib tongue put him in the favors of his father. Perhaps that he was so far down in the succession order that made for an acceptable steward for all involved in the succession. In any case, we know for how long he has held the position.
A leg twisted at birth had earned him the name Lame Lothar. He had served as his father’s steward for the past dozen years.
(Catelyn IV, ASoS)

Being the steward at the Twins, and one of the organizers of the Red Wedding, Lothar has seen most of his elder brothers handsomely rewarded. Here is the glaring question: what has he in mind for himself as a reward for his good service?

Lame Lothar is in position to know everything at the Twins, has the ear of Lord Walder, and can hope to take all the decisions the old man doesn't take himself. It's likely that the maester brings the mail to him – if not to him, it's to Symond, but Symond has been sent to White Harbor. Moreover, Lothar might be the most ruthless of all the Freys.
Lord Walder had ordered the slaughter of the Starks at Roslin’s wedding, but it had been Lame Lothar who had plotted it out with Roose Bolton, all the way down to which songs would be played. Lothar was a very amusing fellow to get drunk with, but Merrett would never be so foolish as to turn his back on him. In the Twins, you learned early that only full blood siblings could be trusted, and them not very far.
(Epilogue, ASoS)

The dialogue between Roose and Lothar for the preparation of the wedding should have been quite entertaining to hear. All political calculations perfectly understood and hidden under a veneer of impeccable courtesy.

Tytos Blackwood is sorry to say to Jaime that his second son is among the victims of the Red Wedding.
Lucas was murdered at the Red Wedding. Walder Frey’s fourth wife was a Blackwood, but kinship counts for no more than guest right at the Twins. I should like to bury Lucas beneath the tree, but the Freys have not yet seen fit to return his bones to me.
(Jaime, ADwD)

Lothar, being a Blackwood by his mother, is thus, chief, and perhaps alone, among all the Freys, guilty of kinslaying (and, I presume, he didn't return the bones because it might curse him in eyes of the old gods at Raventree Hall). In fact, it is not said that Jammos played any role, or was even present, at the Red Wedding. The last son of Alyssa Blackwood, Whalen, might be guilty of kinslaying as well – if one holds against him that he neutralized the Greatjon by filling his cup over and over with wine, and thus contributed to the slaughter.

Are we going to conclude that Lothar perpetrated kinslaying and the violation of guest right just for watching all his elder brothers enjoy their newfound positions? Did I mention he is not afraid of kinslaying?

We see often Lothar in the company of  Bastard Walder before the Red Wedding. They came to Riverrun together to lure Robb Stark to the Red Wedding. Here is Bastard Walder, in the eyes of Daven Lannister.
“And Walder Rivers,” Daven said, “that whoreson. Hates that he’s a bastard, and hates everyone who’s not.
(Jaime V, AFfC)
And later in the eyes of Jaime Lannister.
Walder Rivers stood before his own modest tent, talking with two men-at-arms. His shield bore the arms of House Frey with the colors reversed, and a red bend sinister across the towers. When the bastard saw Jaime, he frowned. There’s a cold suspicious look if ever I saw one. That one is more dangerous than any of his trueborn brothers.
(JaimeVI, AFfC)

Wouldn't a bitter bastard son follow the ambitions of an half-brother? Lothar would easily make an ally of Bastard Walder for his ambitions. Lothar entrusted him of the task of leading the attack on the northmen camp during the Red Wedding. Walder Rivers was with Ryman Frey before Ryman left Riverrun and was ambushed by the Brotherhood.
“How many men did Ser Ryman have with him?” he asked.
“Three knights and a dozen men-at-arms,” said Rivers. “It is almost as if they knew that he would be returning to the Twins, and with a small escort.”
Edwyn’s mouth twisted. “My brother had a hand in this, I’ll wager. He allowed the outlaws to escape after they murdered Merrett and Petyr, and this is why. With our father dead, there’s only me left between Black Walder and the Twins.”
“You have no proof of this,” said Walder Rivers.
“I do not need proof. I know my brother.”
“Your brother is at Seagard,” Rivers insisted. “How could he have known that Ser Ryman was returning to the Twins?”
“Someone told him,” said Edwyn in a bitter tone. “He has his spies in our camp, you can be sure.”
And you have yours at Seagard. Jaime knew that the enmity between Edwyn and Black Walder ran deep, but cared not a fig which of them succeeded their great-grandfather as Lord of the Crossing.
(Jaime VII, AFfC)
What lies behind the dialogue can be understood in various ways.

The singer Tom Sevenstrings is at Riverrun with the Freys, and he might have informed the Brotherhood. However, one can see how Edwyn's mistrust of Black Walder borders on paranoia, and therefore how easy it would be to manipulate Edwyn. Bastard Walder is acting as Edwyn's protector (he had taken the defense of Edwyn some time before in his quarrel with the Pipers and Vances) and main counselor, just as Lothar might have advised him to do.

Here is another interesting plot point that concerns Lothar's wife Leonella Lefford. House Lefford holds the Golden Tooth, which guards the entrance to the Westerlands, and around which the Young Wolf found a providential secret passage. Thus the invasion of the Westerlands was possible, while the Golden Tooth remained untouched. Did Leonella tip the northmen of the secret passage, playing thus an ambiguous double game: betraying the Lannisters while preserving the familial seat? She might not have played any active role, and simply answered a request from her husband.

The trick seems to have been well covered. Indeed, here is another bastard of Lord Walder: Martyn Rivers.
“How did the king ever take the Tooth?” Ser Perwyn Frey asked his bastard brother. “That’s a hard strong keep, and it commands the hill road.”
“He never took it. He slipped around it in the night. It’s said the direwolf showed him the way, that Grey Wind of his. The beast sniffed out a goat track that wound down a defile and up along beneath a ridge, a crooked and stony way, yet wide enough for men riding single file. The Lannisters in their watchtowers got not so much a glimpse of them.” Rivers lowered his voice. “There’s some say that after the battle, the king cut out Stafford Lannister’s heart and fed it to the wolf.”
“I would not believe such tales,” Catelyn said sharply. “My son is no savage.”
“As you say, my lady. Still, it’s no more than the beast deserved. That is no common wolf, that one. The Greatjon’s been heard to say that the old gods of the north sent those direwolves to your children.”
(Catelyn V, ACoK)

It has been made sure that a singer, Rymund the Rhymer, would sing the tale of the Wolf-who-sniffed the goat track.
He closed with the song he had written about Robb’s victory at Oxcross. “And the stars in the night were the eyes of his wolves, and the wind itself was their song.” Between the verses, Rymund threw back his head and howled, and by the end, half of the hall was howling along with him, even Desmond Grell, who was well in his cups.
(Catelyn VI, ASoS)

Thus Leonella Lefford was covered. Later the Freys would invent other tales and attribute fantastic abilities to the direwolves (The wolf's head attached to Robb's body, Jared at White Harbor talking of Robb Stark changing into a wolf etc), to the point of overusing the trick.

Whatever influence Leonella might have over her husband, she shouldn't see with much favor her four daughters not inheriting from Lothar. But, for all we know, she might be completely passive in all this.

This digression gives credence to the idea that Lothar watches what his siblings are doing away from the Twins. Edwyn suspects Black Walder to spy on him, and Jaime suspects Edwyn to spy on Black Walder. I conjecture that Walder Rivers despite counseling Edwyn, might work for Lothar. It is therefore reasonable that Lothar keeps an eye on what is happening in Winterfell.

It's time to end the digression and return to the north.

Lothar's association with Roose Bolton is interesting. Roose and Lothar have cooperated successfully for the Red Wedding.  Surely Lothar has understood the conflict for inheritance at the Dreadfort, and Roose is well aware of the needs of the Freys in matter of titles and lands. They can find themselves objective allies if they need to.

There is no sign that Big Walder is Lothar's agent, or that there is a close relationship between the two Blackwood Freys, except for the fact that Lothar read Big Walder's letter. If we return to the choices of both Walders as the wards to be sent to Winterfell, we recall that Big Walder is not well known to the Lord of the Crossing. It's likely that Lothar lobbied for Big Walder's sending to Winterfell.

Big Walder is an astute observer: he understood that Manderly murdered Rhaegar, Symond and Jared. Big Walder's certainty that he will rule the Twins one day makes sense if he has understood just as well that Lothar plots for inheritance – all in the context of being Lothar's heir, of course. Or simply, as young child Big Walder might have heard a few conversations among the Blackwood Freys and his ambition might be the result of what he happened to have heard.

In any case, Lothar and Big Walder's interests seem to converge.

Theon asks Big Walder if Rhaegar, Jared and Symond have been found.
“No. I never thought we would. They’re dead. Lord Wyman had them killed. That’s what I would have done if I was him.”
(Reek III, ADwD)

If one believes that Big Walder's thinking reflects Lothar's thinking, that means that Lothar knew that the three Freys were risking their lives by going to White Harbor, and perhaps that he has intrigued to send them on purpose.

Lord Godric's reasoning is similar to Big Walder's.
“The Freys were bringing the fat fool a bag of bones. Some call that courtesy, to bring a man his dead son’s bones. Had it been my son, I would have returned the courtesy and thanked the Freys before I hanged them, but the fat man’s too noble for that.”
(Davos I, ADwD)

In all likehood, Ramsay does not care for the subtleties of the politics at the Twins. But Roose probably does. If the plot by Lothar, and Walder Rivers, is real, Roose might be in it in some way. Roose's old friend, Qyburn, offers some advice to Cersei and her small council.
“A little spittle on Lord Walder’s tomb is not like to disturb the grave worms,” Qyburn agreed, “but it would also be useful if someone were to be punished for the Red Wedding. A few Frey heads would do much to mollify the north.”
(Cersei IV, AFfC)

Qyburn's thinking is likely to reflect Roose's, in my opinion. Hence Roose might know that the future ruler of the Twins might not bear him so much grudge for getting the world rid of the Crakehall Freys (Hosteen, Walda, Little Walder).

In particular, Roose should have noticed that Lothar is Big Walder's nephew. Since Big Walder is not fond of Ramsay's cruel amusements, it should be easy for Roose to gain his trust and convince Big Walder to repeat everything he knows about Ramsay. On the other hand, Big Walder might have noticed that Ramsay and Walda are rivals, and he might have understood that Little Walder's situation, as both Ramsay's squire and Walda's brother, is untenable.

7. Little Walder's murder

Here is the discovery of the murder in Winterfell's Great Hall.
Snow slid from Ser Hosteen’s cloaks as he stalked toward the high table, his steps ringing against the floor. A dozen Frey knights and men-at-arms entered behind him. One was a boy Theon knew—Big Walder, the little one, fox-faced and skinny as a stick. His chest and arms and cloak were spattered with blood.
The scent of it set the horses to screaming. Dogs slid out from under the tables, sniffing. Men rose from the benches. The body in Ser Hosteen’s arms sparkled in the torchlight, armored in pink frost. The cold outside had frozen his blood.
“My brother Merrett’s son.” Hosteen Frey lowered the body to the floor before the dais. “Butchered like a hog and shoved beneath a snowbank. A boy.”
(Theon, ADwD)
A few more details follow.
Lord Ramsay descended from the dais to the dead boy. His father rose more slowly, pale-eyed, still-faced, solemn. “This was foul work.” For once Roose Bolton’s voice was loud enough to carry. “Where was the body found?”
“Under that ruined keep, my lord,” replied Big Walder. “The one with the old gargoyles.” The boy’s gloves were caked with his cousin’s blood. “I told him not to go out alone, but he said he had to find a man who owed him silver.”
“What man?” Ramsay demanded. “Give me his name. Point him out to me, boy, and I will make you a cloak of his skin.”
“He never said, my lord. Only that he won the coin at dice.” The Frey boy hesitated. “It was some White Harbor men who taught dice. I couldn’t say which ones, but it was them.”
(Theon, ADwD)
The Walders do not appear in the story afterwards.

There is at least one obvious thing to notice: the blood on Big Walder. The blood splattered on Big Walder's body would seem to accuse him: His chest and arms and cloak were spattered with blood and little later The boy’s gloves were caked with his cousin’s blood. So it's not possible that the blood came on Big Walder from his cousin, if he has just discovered the body below the snowbank.

In the perspective of Big Walder's ambition to rule the Twins, of his lack of compassion displayed at the news of Stevron's death and of his cold-blooded suspicion that Manderly murdered Jared, Rhaegar and Symond, the observation leads many to think Big Walder killed his cousin.

The situation is reminiscent of Arya's murder of the Bolton's guard in her final moments in Harrenhal.
“Silver, you say?” He did not believe her, but he wanted to; silver was silver, after all. “Give it over, then.”
Her fingers dug down beneath her tunic and came out clutching the coin Jaqen had given her. In the dark the iron could pass for tarnished silver. She held it out... and let it slip through her fingers.
Cursing her softly, the man went to a knee to grope for the coin in the dirt and there was his neck right in front of her. Arya slid her dagger out and drew it across his throat, as smooth as summer silk. His blood covered her hands in a hot gush and he tried to shout but there was blood in his mouth as well.
“Valar morghulis,” she whispered as he died.
When he stopped moving, she picked up the coin. Outside the walls of Harrenhal, a wolf howled long and loud. She lifted the bar, set it aside, and pulled open the heavy oak door. By the time Hot Pie and Gendry came up with the horses, the rain was falling hard. “You killed him!” Hot Pie gasped.
“What did you think I would do?” Her fingers were sticky with blood, and the smell was making her mare skittish. It’s no matter, she thought, swinging up into the saddle. The rain will wash them clean again.
(Arya X, ACoK)

Let's leave aside the value of this scene as a foreshadowing of Arya's carreer as an assassin, and the symbolic value of the monetary exchange that goes along the murder. The common elements with Little Walder's murder are: the promised silver coin (in reality an iron coin), the hands covered in blood, the frightened horses, the murderer is a child, the presence of Roose Bolton as master of the castle. It shows clearly how Big Walder could have killed his cousin.

This is all that can be said in favor of incriminating Big Walder for the death of his cousin.

It's not impossible that Big Walder, a boy of nine, would kill another child, even his cousin, despite the stigma of kinslaying. But it is, a priori, not very plausible. It's true that the two Walders were behaving differently as Ramsay's squires, and that Little Walder was Ramsay's favorite. But there is no sign of dissension between the two boys.

Killing Little Walder is hardly a strategy to rule the Twins. Big Walder's strategy, if he has one, should be what we just saw: let Lothar do what is needed, and wait. If Big Walder is that machiavellian, he shouldn't do his killing himself, which is likely to put him in big trouble. Given the tension between Ramsay and the Freys, there is a good chance that Little Walder will disappear by himself.

But Big Walder appears to be astute. Why would he leave traces of blood on his body? Everybody in the Hall is just as well placed as we are to formulate suspicions. Arya is concerned about the blood on her hands and thinks that the rain would wash them (of course, we know that she is deluded and that she is marked as a murderer now). The murder happened a few hours ago, since the blood on the body is frozen, so Big Walder has had the time to wash his hands, change his clothes etc. If he hasn't done so, it's because he doesn't feel to be at risk of being accused.

The fight between Hosteen and Manderly that followed shows us that the use of a sword does not lead to much blood splattering.
Hosteen Frey’s sword was red almost to the hilt. Blood spatters speckled his cheeks like freckles.
(Theon, ADwD)

But I could imagine that Big Walder has transported the body – or helped transported it, since I doubt he his strong enough to carry his much heavier cousin.

However, Big Walder tells neither only the truth nor all the truth. We will return to the murder, and offer a different theory. Indeed, there are several observations to make about the murder. I count at least seven which do not lead to the culpability of Big Walder. All this will be part of the examination of the final scene in the Great Hall, a larger subject than the murder itself.

The Winterfell Huis Clos