Walder Frey is undoubtedly one of the worst characters still alive on Game of Thrones. He played a big part in orchestrating the Red Wedding (along with Tywin Lannister and Roose Bolton), one of the darkest and most gruesome events in the show's history. Given the trailer for the June 26 season finale and the recently-released promo images, it seems very possible that Walder Frey will die during the sixth season finale of Game of Thrones.
In the finale trailer, we catch a clear glimpse of the Freys and the Lannisters celebrating the re-taking of Riverrun, a feat accomplished largely thanks to Jaime Lannister's ruthlessness — he threatened Riverrun heir Edmure Tully's child to convince Edmure to turn on his family and allow Jaime's forces to take back the castle.
Now, this is a season finale we're talking about. The likelihood that we'd spend precious finale minutes with a party full of people we hate, if nothing crazy or twist-y or vengeance-y goes down? Super unlikely. It's even more unlikely knowing that, in order to fit everything in, the showrunners needed to extend the running time of the final episode of the season to an unprecedented 69 minutes.
On top of all that, the parallels to the Red Wedding in the brief preview of this scene are all too clear. It's a celebration (where people typically aren't expecting chaos and cold-blooded murder), and gross Walder Frey even echoes a version of that iconic line spoken by the late Roose Bolton at the Red Wedding. "The Freys and the Lannisters send their regards," Walder says in the promo, toasting to the assembled men with a smug look on his face.
If old Walder finally bites it during the finale, only one question remains: Who is the one to actually kill him? There are a few promising theories.
One particularly astute Redditor named Kaztrator pointed out that two of the three main culprits of the Red Wedding were each killed by one of their sons (Tywin by Tyrion, Roose by Ramsay). Kaztrator suggested that one of Walder's sons might slit his throat – only for the murderer to then "unmask" themselves and turn out to be Arya. It remains to be seen whether Arya can actually still face swap while away from the Faceless Men, but you have to admit that this would be deliciously poetic justice – and she'd get to cross a name off of her ever-growing list!
One Of Walder's Many Children
Alternatively, one of Walder's children or grandchildren might finally decide that they've actually had enough of this incompetent old guy leading them into all manner of risky situations and kill him mid-party.
It seemed strange that the show would have reintroduced the Blackfish only to then do nothing at all with him (and have him die offscreen, no less). Who's to say he couldn't pop back up and finish off the man who conquered his family's castle?
Somebody Sent By Jon And Sansa
They probably want some downtime after the huge Battle of the Bastards, but they could potentially send out a small force to take out the man who killed their brother and Catelyn. I just really want it to be a Stark or Tully who ends Walder.
Redditor Full_0f_Sh*t suggested that Jaime could kill Walder in order to replace him with Bronn as the Lord of the Crossing and Riverrun, once word gets out that the Starks have retaken Winterfell, because he knows that useless Walder has no hope of defeating the Stark forces. But my favorite version of this theory is that Jaime kills Walder to save Brienne, who would potentially have been captured (along with Pod) by Frey forces as they were fleeing Riverrun.
It's plausible – we haven't seen hide nor hair of those two fan favorite characters since they got away from the re-taking of Riverrun via boat. We already know that Jaime has a softspot for (and bond with) Brienne. While turning on the Freys would be a risky and potentially dangerous move just to save one person, the Jaime/Brienne 'shipper in me adores this idea. Jaime needs to get back on track with his redemption arc, anyway.
Whoever ends up doing the deed, one thing is for certain — no viewer (and no in-universe character) will miss Walder Frey.