The writer has previously insisted that Stoneheart will not feature as Game Of Thrones builds towards its final eighth season, but fans remained adamant that she was present during Arya's brief exchange. Littlefinger took care to mention the sequence of events the dagger set into motion.
Then there's the way she fights Brienne, her tactics borrowing from the her time with Jaqen and the Waif - the way she bounces off the floor - and with the Hound.
Secondly, Littlefinger has to realize Bran knowing all means the young Stark knows Littlefinger betrayed Ned and sparked the War of the Five Kings.
Some background, in case you forgot: In the books, Catelyn Stark comes back to life after the Red Wedding as Lady Stoneheart, and she roams around the countryside searching out Freys and serving up vengeance. "Chaos is a ladder".
The show, perhaps to simplify things or to make Jon's resurrection have more impact, didn't include Lady Stoneheart. And some, are given a chance to climb.
At the end of season six, the Starks have finally begun putting back the pieces of their family's shattered remains; Jon and Sansa are reunited and attempting to take back the north. But also because it shows Littlefinger that Bran/Three-Eyed Raven understands his games, presumably knows Baelish was basically responsible for Ned's death. It's only a matter of when. People are so very different, even though they're the same person in the same place, who they've become is so different. Littlefinger may not have been directly responsible, but he could have helped the person who hired the assassin. Littlefinger told her it was his, but he lost it in a bet to Tyrion Lannister.More news: Jennifer Rubin: North Korea options
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Before you read any further beware, for there lay spoilers ahead.
Is the dagger's placement coincidence?
Because of this foiled murder plot, Catelyn headed down to King's Landing, never to return, and asks the palace's many Machiavellian men who it belongs to.
Catelyn is no longer around, but Bran and Littlefinger are and since they have the dagger, this could convince the individuals still loyal to the Lannisters to turn to the other side.
Maybe - maybe - this is an intentional homage to the missing, undead book character, but that's about it. Game of Thrones is full of mysteries, secrets, and Easter eggs, but it's better than actually bringing a character back from the dead in the background.
Amy Ratcliffe is a writer for IGN and wouldn't last a day in Westeros.