Re: SPOILER *all five books* THREAD FOR Game of Thrones (TV series discussion)
It's not going to be Euron, his story lies elsewhere. He's going to be involved with Vic and Dany, possibly even shit to do with The Others. He's sailed all across the world, been as far as Asshai and he's been to the smoking ruins of Valyria, where no other man has walked. He knows a lot of shit, he's gonna be tied in with the mythical side of the story. It wouldn't be fitting for him to kill Cersei.
The valonqar has to be either Jaime or Tyrion. Jaime would be much more satisfying though. The only other possible valonqar who isn't Jaime or Tyrion and who would be fitting and satisfying enough would be Stannis. But I don't think we're ever going to see Stannis back in the South or Kings Landing. His fate is in the North.