When you think of the characters pulling the strings behind the scenes on Game of Thrones, Petyr Baelish and Varys come to mind. People who conspire in the dark, gathering information and making dramatic speeches about chaos as a ladder. But there’s another mastermind who doesn’t make speeches, which makes him the most dangerous of all: Arya’s dubious assassin-tutor Jaqen H’ghar. Even though he hasn’t appeared in Season 7, there’s evidence that he might make a comeback.

Since Arya left Braavos and the House of Black and White behind at the end of Season 6, you might think Jaqen H’ghar is gone from the story. But if he’s got the long game the story has implied he does, a man will be back.

At the end of Season 2, Jaqen gave Arya the coin that was basically her invitation to join the Faceless Men. In Seasons 5, Arya finally RSVPed and showed up at the House of Black and White. Throughout Seasons 5 and 6 he spent time grooming her, teaching her their ways. As a payoff, at the end of Season 6, Arya killed his star student (the Waif) and ditched the House of Black and White to return to Westeros, dropping out of Assassin School. In response, Jaqen didn’t say “Wow, rude. Thanks for a massive waste of my time.”

Instead, he smiled, as if all was going according to plan.

Maybe this is just wonky writing. But, it could also mean that Jaqen is still in the game for the wars to come, and Arya acted in accordance with his hidden agenda.

This wouldn’t be out of the blue — in the books, a Faceless Man implied to be Jaqen shows up at the Citadel and obtains a key that can open every door. Although it isn’t explicitly stated, he’s likely looking for a book called The Death of Dragons, whose only copy is in a locked vault in the Citadel.

Why would he want this book? One long running theory posits that the Faceless Men were responsible for the Doom of Valyria, the mysterious cataclysmic event that took down the most advanced civilization in the world years before the events of Game of Thrones.

In both the TV series and the books, Valyria is a ruin where the Stone Men go. But once upon a time it was a hub of knowledge, culture, and dragonlords.

Unfortunately, it wasn’t all fun and dragons. The dragonlords also had slaves who toiled away in mines beneath volcanic mountains. And as Arya learns in the books, the origins of the Faceless Men trace back to these slaves. In the show, Jaqen simply tells her that the first Faceless Man was “no one.”

If the Faceless Men once lived awful, oppressed lives under dragonlords and brought their entire society the gift of death as a result, it stands to reason that they aren’t thrilled about the resurgence of dragons in the story’s current timeline. There’s plenty of motive for them to engineer a second Doom to ensure that a second era of dragonlords will not come to pass.

George R.R. Martin has also supplied evidence for this theory, in the form of comments about how he’s influenced by The Lord of the Rings. He’s particularly cited his admiration for the Scouring of the Shire — in which the hobbits return to find the Shire spoiled and ruined, which was left out of the Peter Jackson films. From a 2015 interview with The Observer Martin said:

I mean, it’s no secret that Tolkien has been a huge influence on me, and I love the way he ended Lord of the Rings. It ends with victory, but it’s a bittersweet victory…And the scouring of the Shire — brilliant piece of work, which I didn’t understand when I was 13 years old: “Why is this here? The story’s over?” But every time I read it I understand the brilliance of that segment more and more. All I can say is that’s the kind of tone I will be aiming for.

Having a miniature version of the Doom of Valyria in Westeros would certainly be an unexpected, wrenching footnote to the Great War between the living and the dead.

As for how Arya fits into Jaqen’s grand plan, if he is indeed orchestrating a second Doom? That part is less certain. Perhaps Jaqen liked the idea of unleashing his favorite student in Westeros, knowing that Daenerys would likely make her way onto Arya’s kill list. Or perhaps it was wonky writing in Season 6 when he smiled at Arya after she flunked out of Assassin School.

Either way, the last big twist on Game of Thrones could very well be that the ultimate threat is not the Night King or Euron Greyjoy. When all is settled and done and the dust settles after the final conflict, there’s still the threat of no one.

Game of Thrones Season 7 is currently airing Sunday nights on HBO.

Photos via HBO