Remember back in Season 5, when there was a flashback to a young Cersei visiting Maggy the Frog, who prophesied that Cersei would marry the king and have three children, all of whom would die?
1.Tyrion will kill Cersei
2.Jaime will kill Cersei
3.Arya will kill Cersei
4.Sansa will kill Cersei
5.Daenerys will kill Cersei
6.Cersei will die in childbirth
7.Cersei will take herself – and everyone else – out, full Mad Queen-style