Game Of Thrones: 10 Theories On Who Will Kill Cersei Lannister

2. Herself

Cersei has been cast down by a younger, more beautiful Queen (be it Margaery, Dany, Sansa, whoever). All of her children have died, and she's lost all she holds dear: her kids, her power, and Jaime. She's essentially just waiting for the valonqar to finish her off, going mad with grief. Rather than waiting for someone else to come and kill her, probably still Tyrion in her mind, she decides to kill herself using... the strangler. She becomes her own valonqar. That said, this theory either forces you to abandon the idea of the valonqar being the one to kill her (which fits with her own reasons for committing suicide), or believe in another, slightly more out-there theory: that her and Jaime are secret Targaryens. It's long been speculated that Tyrion may be, but a counter to that is that it's his elder siblings who are the true children of Aerys (and this would make Cersei a younger sibling). We've already seen signs of madness in Cersei, and it would be quite fun to see Lena Headey play her as increasingly deranged, like another coming of Aerys II...