I think Lady Stoneheart will die, someone will “kill” (she’s already dead though) her. Once she’s “dead”, the Brotherhood Without Banners will be in need of leadership as I think they’ve proven that they need guidance.
Now I have speculated about Arya and how she’s going to return to Westeros/what she’s going to do to impact the war with the Others and the climax of the series multiple times. The problem is Arya can go in so many different directions because she’s just such a wild card as a character. She’s amassing all these skills, allies, knowledge, and experiences, which we know will do something, but what?
There’s the Hardhome theory, which has merit. Arya meeting up with Dany makes some sense, too.
But I will admit that the theory/speculation I always return to is Arya returning to the Riverlands- which is why I brought her up here. People don’t seem to realize that even including the Mercy chapter, Arya has had more chapters with the Brotherhood Without Banners than the Faceless Men. They were a huge part of her character arc and not one to be taken lightly.
What connects Arya to Westeros and her old life? Her family and her bond to Nymeria primarily.
And who is actually looking for Arya still? Brienne, the Brotherhood Without Banners, and the Wall/Ramsay plot.
Looking at it, it seems like the Riverlands makes sense.
- The BWB are there. They are introduced to us through Arya, she has close bonds with a few, and is held with affection by others. Besides, they have been searching for her for a while as we have been reminded over and over. It makes sense that Arya will meet up with them again. There’s no other reason I can see that will make them get involved in what’s to come otherwise. They definitely are not fans of Jaime or Brienne, the other POVs that they have dealings (or future dealings) with.
- There are only so many ports that Arya can enter into Westeros from. The Saltpans seems logical compared with other options. And since it was the way she left, it makes sense that it would be the way she gets back.
- Nymeria. Full stop. Nymeria isn’t leaving the Riverlands. She has been there for five straight books. And now she has the pack to consider. Even for Arya, I can’t see Nymeria leaving the place she’s been so long without reason. I think Arya’s going to have to pick her up to be honest. The pack, too. I feel like it must have some significance (see here,) since it has been so heavily referenced. It’s one of the chekov’s guns waiting to go off. Nymeria’s in the Riverlands, Arya’s definitely reuniting with her, I think she’s going to have to go to her though- after all, she’s the one who against her will drove her away. There’s definitely hints that Nymeria was chasing after Arya in ASoS though,
- Brienne’s there and not looking like she can leave any time soon (what with the BWB.) She’s looking for Arya, too.
- Arya continues to feel connected with the Riverlands even in the House of Black and White. She even thinks about how it’s snowing there. She sees it through Nymeria’s eyes.
There are a few minor reasons why as well, but those are the big ones.
It isn’t impossible that Arya will be the one to “kill” Lady Stoneheart. She was the one who found Catelyn’s body in the river and alerted the BWB through Nymeria. She tried to save Cat and was miserable over the guilt of being unable to even though she was at the Red Wedding. Moreover, Lord Beric promised to reunite Arya with her mother, which is at least part of the reason why he gave her back her life.
Also, so much involving LS we see through Arya- Arya as Nymeria saves her body, Arya’s former companions the BWB are the people she travels with, we have the whole “wolf with a fish in it’s mouth”, “can you bring back a man without a head?”, and “you should have saved my mother” stuff just waiting to play out completely. Arya fixates on Catelyn’s death way more than Robb’s too. This could be why.
The point is that Lady Stoneheart (less so than Catelyn herself in a lot of respects) is tied to Arya’s storyline.
Then there’s the fact that around the time of LS and the Red Wedding, Arya was taught the “gift of mercy” by Sandor. That definitely seemed to be building somewhere, but when it came up (i.e. when Sandor was dying and asked for mercy,) Arya didn’t do it. The whole concept of the “gift of mercy” that Sandor tried to instill in Arya hasn’t really played out yet. I wouldn’t be surprised if it comes to play with LS.
It would be a mercy to put Lady Stoneheart to rest. She’s become unrecognizable from her former self and is a tormented figure to the extreme. The idea of the “gift of mercy” returning when Arya sees Lady Stoneheart and gives it to her makes sense.
Not to mention how symbolic it would be. A lot of fandom mischaracterize Arya as a revenge-obsessed when she really isn’t. She’s not searching people out to kill. The only time she’s consciously taken revenge (in the chapter entitled “Mercy” no less) was when the guy stumbled onto her. It’s not her focus or priority and her list functions as a coping mechanism first and foremost. More so, she doesn’t ever extract justice on bystanders, innocents, or people considered guilty by association (i.e. why she doesn’t kill Raff’s companion, a Lannister man, because to her he’s done no harm just because he’s a Lannister man and Raff’s companion in “Mercy”.) She’d never harm anyone who she doesn’t know is bad- which is why she watches her assassination target for days to determine that he’s “evil” first.
But Lady Stoneheart (and by extension the BWB as a whole) subvert that so hard. Everyone at all associated is guilty- right down to people like Pod, who’s a kid- and deserves to hang. All they care about is vengeance, they’re not even really taking care of the smallfolk anymore because of it. They’ve become a part of the problem they were fighting.
So it’d be symbolic of Arya saying no to blind vengeance as well. And it’d be a way of correcting and focusing the path that the BWB have fallen off of since Beric’s death.
I could see Arya leading the BWB (who are definitely going to have some big part to play regardless) to the Wall/battle with the Others, along with the giant pack of wolves that are just waiting to be utilized.
"You know, I don’t like to give things away." says Martin, a grin spreading across his face. "But you don’t hang a giant wolf pack on the wall unless you intend to use it." (x)
So that’s my theory on what’s going to become of Lady Stoneheart/BWB.