New 'Game of Thrones' fan theory adds a delicious twist to this Season 7 death

It's been so long since we got a new book in George R. R. Martin's A Song of Ice and Fire series (six years and counting), it's sometimes easy to forget that anything exists outside of HBO's Game of Thrones.

David Benioff and Dan Weiss' adaptation has deviated pretty dramatically from its source material at this point -- some major characters who are dead on the show but still alive in Martin's novels include Stannis, Shireen, Selyse, Myrcella and Tommen Baratheon; Ramsay and Roose Bolton; Rickon Stark; Walder Frey; Mance Rayder; the Tyrells; Hodor; Shaggydog; Summer; pretty much everyone in Dorne, and the show's most recent fatality, Petyr Baelish.

Our dearly departed Littlefinger is the source of an intriguing new Reddit theory, which also involves another character who was substantially altered between the books and the show: Catelyn Stark, who was resurrected by Beric Dondarrion and now goes by the name Lady Stoneheart in ASOIAF.

In the books, Lady Stoneheart assumes command of the Brotherhood Without Banners and goes on a killing spree, taking out anyone associated with the Lannisters, Freys and Boltons in revenge for the Red Wedding.

The show has apparently decided not to utilize Lady Stoneheart -- perhaps to maximize the "surprise" of Jon Snow's resurrection at the beginning of Season 6 -- and has instead allowed her daughters, Arya and Sansa, to take over some of her plot points.

This has led one Redditor to speculate that the show might be giving us a big clue about Littlefinger's fate in the books, with Sansa filling in for her vengeful mother.

The theory definitely makes sense -- there's something suitably poetic about Catelyn being the one to dispatch Littlefinger after all the chaos and misery he's caused her family over the years, and a kangaroo court presided over by a murderous reanimated corpse makes way more sense than Arya and Sansa faking a rift just to publicly trick their nemesis.

No wonder George R. R. Martin once admitted that the decision to omit Lady Stoneheart from the show was one of the changes he argued most vehemently against during discussions with Benioff and Weiss.

"I think one of the biggest ones would probably be when they made the decision not to bring Catelyn Stark back as Lady Stoneheart. That was probably the first major diversion of the show from the books and, you know, I argued against that, and David and Dan made that decision," he told Time. "In my version of the story, Catelyn Stark is re-imbued with a kind of life and becomes this vengeful wight who galvanizes a group of people around her and is trying to exact her revenge on the riverlands. David and Dan made a decision not to go in that direction in their story, pursuing other threads."

Luckily, if fans are unsatisfied by the showrunners' decisions, they can take comfort in the fact that they'll be able to read Martin's original vision for his story... someday.