I have a feeling Sansa's marriage to Tyrion will come into play and Tyrion will try to make a claim on her and the North (and I can't wait to see Jon Ghost kicking his ass, which was promised in AGoT)
I’m still holding out hope it will be Arya.
Isn’t her very first line in the Show “Where’s the Imp?” While he’s off in a brothel with redheaded Ros (rose), no less.
She’s the only Stark (apart from baby Rickon) who we have never seen interact with Tyrion.
But she has an interesting interaction with Bobono in TWOW Mercy. He’s so over-the-top Tyrion-rific and their positions echo that of Ros and Tyrion in the Pilot. It is implied, in the play she plays the Sansa character while he plays the Tyrion character, involving a rape scene. The play is about the purple wedding, but probably also Tyrion’s own wedding to “a maiden”. So their animosity is framed by Tyrion’s marriage and threat to Sansa. Much like the Titan image frames Littlefinger’s threat.
Bobono molests Mercy, and as they interact she keeps threatening him, and then later she pretends to seduce an old foe to serve him some long overdue vengeance with Needle, while Bobono gives a villain speech on stage:
"Give me the cup," he told the Stranger, "for I shall drink deep. And if it tastes of gold and lion's blood, so much the better. As I cannot be the hero, let me be the monster, and lesson them in fear in place of love."
When you compare AGOT Arya I and Mercy it’s not that dissimilar: needles and stitches, wedding speculation, Sansa and a tall handsome prince (anti-Tyrion), the great honor of visiting guests, chatting girls, observations of a “show” from a distance, sigils on surcoats, having to run back, first lines and last lines… Jon and Arya consider something deeply unfair, and later Jon will give her Needle to ameliorate the situation for her a little. Needle comes up again in the conversation she shares with Ned about her and Sansa’s futures. Sewing remains a theme in their conflict, when Arya destroys Sansa’s betrothal dress with the juice stain and offers to make a new one. Arya, Sansa, Needle, Jon, and marriage have a link.
On the Show, they echoed a lot of the pilot episode when Dany comes North. Obviously, they deviated far from the original goal. But if Sansa’s marriage to Tyrion is still an issue (in a “brothel” with a redhead) by the time Stark and Targ collide, then Arya’s interest in “the Imp” might then connect to posing a threat to a dwarf who is turning evil in context to his marriage to Sansa. Cue “sewing”.
Ghost eating Tyrion, or Jon beheading him, is too clean. Tyrion’s sharpest weapon is his mind, and his greatest torment should be psychological. Like Mushroom the dwarf, he might think he will have escaped all justice to write his own history, but at the last moment, something will get him. I don’t buy his survival. He is beyond redemption, and he would still prefer to live, if only at the Wall, and honestly, that’s too good for him. Justice for Shae.