Place your bets: Who kills Cersei?
Of course she's got to die, the fans will rise up and riot in the streets if she doesn't! And the show included the prophecy that she would have *three* children who would predecease her, which has already happened, and then someone younger and more beautiful would take everything from her. Of course the show didn't include the part that said "the valonquar (younger sibling)" would be the one to kill her, not that almost everyone in Westeros isn't a younger sibling or a member of an order that calls itself a brotherhood or sisterhood. So eldest siblings are eligible, too.
So far, the chatter seems to favor Jamie as the one to kill her, and "Brienne the Beauty" as the one to take her queen's crown away. But I like my dark horse entry: Dario! Maybe he and his SECOND SONS are among the mercenary companies that came from Essos.