**BIG BIG SPOILERS for A Storm of Swords and possibly for Game of Thrones season 6, you have been warned. Also spoilers for previous seasons.**
Like all adaptations, Game of Thrones has often been criticised for the way it diverges from the original text, and speculation is high for what will make it into the upcoming Season 6.
Now, the books of A Song of Ice and Fire are vast, we're up to five now with each reading at between 700 - 1100 pages, and the world contained within their pages is the definition of epic. There's so much going on in the way of characters and adventure and politics that it can be hard to keep up; it was always going to be impossible to do a faithful adaptation because of just how much happens. So the show switches characters around, changes bits and pieces and leaves a lot out (though to be fair, it does do a pretty good job of adapting the central narratives).
Anyway, as much as I love the books, my point is that its not really fair to criticise the show for not adapting every sub-plot and including every character as the boundaries of the different media make that impossible; but there is a certain character and a certain event from the books that the show has thus far skimmed over completely and it's one that provides one of the more pivotal twists of the series...
What Happens After The Red Wedding?
Now I'm sure that everyone remembers with a painful clarity the events of the infamous Red Wedding.
So, after the Red Wedding you may remember what happened to the bodies of the Starks. The Freys decapitated Robb (Richard Madden)'s corpse and replaced his head with the head of his direwolf, Grey Wind, putting the body on display to mock the King in the North. Catelyn (Michelle Fairley), on the other hand, was unceremoniously stripped and thrown into the Trident to rot.
But that's not the end of the tale for Lady Stark.
The Lightning Lord, Beric Dondarrion, was a slightly pompous knight appointed by Ned Stark to capture the Mountain, Gregor Clegane back in season 1. His party are ambushed at the Mummer's Ford; he is mortally wounded by the Mountain and dies that evening. He was accidentally resurrected by Thoros of Myr through performing the rites of the Lord of Light, and thereafter became the leader of the Brotherhood Without Banners - outlaws who protect the smallfolk in the name of the late King Robert.
He died several more times, but was brought back by Thoros each time, losing a little more of his memory and self each time around. His body bears each mortal injury that he has suffered, and he longs to be allowed to die.
The Lady Stoneheart
During A Feast for Crows we learn that the Brotherhood found Catelyn Stark's body three days after she was murdered and dumped in the river. Beric sacrifices the power that keeps bringing him back to life, passing it onto her instead.
And so Lady Catelyn Stark is resurrected as the Lady Stoneheart.
"The Freys slashed her throat from ear to ear. When we found her by the river she was three days dead. Harwin begged me to give her the kiss of life, but it had been too long. I would not do it, so Lord Beric put his lips to hers instead, and the flame of life passed from him to her. And... she rose. May the Lord of Light protect us. She rose." - Thoros
Like Beric, who bore the wounds from his deaths, Catelyn's throat doesn't fully heal, her skin still split at the neck. She cannot speak without holding closed the cut on her throat, and when she does speak she is hard to understand. She takes the title Lady Stoneheart as she is consumed with hatred and the desire for revenge against those who killed her family. Physically she is mutilated, her skin grey and partly decomposed from the three days she spent in the river. Her hair has thinned and turned white and brittle, and her face is covered in scratches from where she clawed at it in agony when Robb died.
She takes Beric's place as leader of the Brotherhood outlaws and leads them to take revenge upon those who wronged her in life - the Lannisters and their collaborators. Lady Stoneheart is merciless, hanging all those who she believes betrayed her and her family. She kills anyone associated with the Freys, Lannisters or Boltons even if they didn't partake in the Red Wedding.
Will She Appear In Season 6?
Last year Michelle Fairley said that she didn't believe that she would be returning to the series;
"Yeah, the character’s dead. She’s dead. You respect the writers’ decision. They can’t stick to the books 100 percent. They have got to keep it dramatic and exciting, and extraneous stuff along the way gets lost in order to maintain the quality of brilliant show."
On the other hand however George R.R. Martin has spoken about Lady Stoneheart's role, explaining that she is an important character who will have a central role in the upcoming books. Given that he's already given the show writers an outline of how the story will end, it could be that they're just holding the Lady Stoneheart cards close to their chest for now.
Personally I'd love to see Lady Stoneheart make an appearance. Both her and Catelyn are really strong characters in the books, and after all the terrible things that happened to the Starks it would be oh so satisfying to see them finally getting some revenge.