What if Theon Greyjoy didn't betray Robb Stark at all and instead accompanied him all the way including the Red Wedding and Rickard Karstark didn't kill the Lannister squires. There will be some alternate endings to the fateful event.
"You not going in Greyjoy?" Lord Karstark asked as he drank from his mug. "Nope, I do not like parties ever since I was a lad." Theon replied laughing. "I'm glad you made the right choice Greyjoy, I shudder to think what might happen if you listened to your father." Lord Karstark said as he gazed at the stars in the sky. Theon took a sip from his mug and replied "Aye, and I also shudder to think what will happen if you killed those Lannister boys."
"Luckily I didn't, if not for your consultations, I would have." Lord Karstark said with a grin just as Brynden Tully sat next to them. "Gods, I need to take a piss but yet I can't find a perfect tree!" he exclaimed "Maybe the trees thought that your cock looks like a withered flower." Lord Karstark said and the three men burst into laughter. "So, Blackfish, what's going on in there?" Theon asked.
"Everyone is drinking, eating and doing their own shit. But somehow I feel that something terrible is going to happen, it may just be my worries." Brynden answered as he threw some dried grass into the fire. Just then, they heard people cheering and chanting "Bed! Bed! Bed!" as they carried a woman and a man up the stairs. "Looks like the bedding has begun." Lord Karstark said just as the doors to the hall closed. "Why would they close the door?" Brynden asked looking at the door confused.
Theon stood up as he heard 'The Rains of Castamere' playing from within the hall. "Something is wrong." he said. "I agree." Lord Karstark stood up as well followed shortly by Brynden. "Gather the men, in case they're plotting something. I'll free the direwolf." Theon said. After discussing the plan, the three men parted, Lord Karstark heading to his camp to gather his trusted men, Brynden rounding up some of his best archers while Theon walked towards the cages where Grey Wind is held.
Lord Karstark walked towards his camp and saw that the Frey guards were trying to make his men drunk "What the hell do you think you're doing!" he yelled. "We're just having fun my lord." one of his men replied. "I need a few men to come with me, we need to slaughter a boar for the wedding." he ordered and twelve of his twenty men stood up.
"My lord, where are we going? I thought we were supposed to kill a boar?" a Karstark soldier asked.
"Listen, I think that the Freys are plotting against our king, we are supposed to meet up with Theon and Lord Brynden before kicking down the door to the hall." Lord Karstark replied. I hope we're not too late he thought to himself as they made their way back to The Twins.
Brynden Tully approached a table filled with Stark soldiers "Theon thinks that the Freys are plotting against our king, and I need a few men to take up position on the third floor with their bows at the ready." he said in a soft voice. "It'll be done my lord." one of the Stark soldiers replied as a few of them begin to stand up.
Theon moved slowly towards the cage and sliced the throat of a guard stationed there and opened the cage door, Grey Wind came out and looked at him. "Your master is in danger, we're going to rescue him, and I need you to stay alert." he said and the direwolf responded by wagging it's tail.
In less than two minutes, the three men met up outside the hall. "The archers have already taken their positions on the third floor." Brynden said "And I have made sure that the news spread from soldier to soldier." he added. "My men are ready to do their part." Lord Karstark said as his men nodded. "Good, Grey Wind is on the look out for anything suspicious while we enter." Theon said as he took position at the door "Ready?" he asked.
Meanwhile, inside the hall where the wedding is taking place. Catelyn Stark noticed that Roose Bolton is wearing a chain mail underneath his clothes, she stood up and slapped him on the face before yelling "Robb!"
Robb turned and saw Lothar Frey approaching his pregnant wife with his dagger drawn just as an arrow struck him on the temple, and he fell to the ground dead. Just as that happened, the door was kicked open revealing Theon and a few Tully and Karstark soldiers. The Stark archers revealed their locations and pointed their bow and the musicians as Theon entered with his sword drawn "Lord Walder Frey, you are found guilty of plotting against your king, do you have anything to say traitor?" he asked as more soldiers came in with swords drawn.
Lord Walder laughed as he stood up "Do you think you can save your army? They're being put to the sword right now!" he said with a huge smile.
"Theon! We have successfully overpowered the Frey guards, without your help, we would have been killed!" the Greatjon exclaimed as he entered the hall his armor filled with blood stains. "Well?" Brynden said mockingly. "Kill him my king! He deserves it!" Lord Karstark shouted as a few more "Aye!" could be heard.
Robb looked at Walder Frey straight in the eye "I came here for my uncle's wedding even though I should be fighting a war, I ate your bread, I accepted your punishments and this...this is how you repay me!" he yelled "And you, Lord Bolton, I trusted you with my life, I thought you would help me take Casterly Rock from the Lannisters but instead you ran to them!" he said angrily. "Take them both outside! I will personally behead them myself." he ordered as Theon and Brynden grabbed the two men out.
"And what of their men?" the Greatjon asked. "Kill them, kill them all!" Robb replied.
Lord Karstark threw the Frey guards a disgusted look "Luckily for you, you didn't kill the king. Because if you did, you would be a dead man. Why? Because, the Northerners will never ever forget." he said coldly. "Well, let's get the bloodbath started! Kill those damn Freys!" he shouted as the Stark soldiers begin hacking and slashing while the archers rained arrows upon any Frey guard that tried to escape.
After the beheading of both Roose Bolton and Walder Frey, Robb gave Theon a brotherly hug and thanked him profusely for saving his life. "Arya?" Theon said with shock. Robb turned around to find Sandor Clegane approaching with a sleeping girl in his hands. "Your Grace." Sandor said and handed Arya over to Theon.
"Name your price, Sandor and you shall have it." Robb said. "I ask none, except to let me serve in your army as a captain, it's all I ask." Sandor replied. "It shall be done, I swear it upon the old gods and the new, that Sandor Clegane shall be named captain of the guard." Robb replied.
The news of the entire elimination of Houses Frey and Bolton reached King's Landing, and Tyrion Lannister laughed when he heard about it. "That's why they called him the young wolf! It won't be long before he's at our gates, trust me." he said.
"Your Grace! Robb Stark is at the gates." one of the goldcloak reported. "Told you." Tyrion said.