Jaime Lannister may end up as a thorn in Cersei's side and she might just kill him for it. Or maybe it might be the other way around. Jaime Lannister, "The Kingslayer" started off as a despicable pretty boy who engaged in incest but over the course of several seasons, the character has grown and changed into someone that fans actually root for.
But a conscience may cost Jaime as his sister and companion Cersei has steadfastly remained a treacherous villain throughout the series and with what we saw of her in the last season, that may not change so Jaime will have to make a choice, will he stand by her sister through to the end or will he turn his sword on her for the good of Westeros and the other kingdoms. Will Jaime Lannister become "The Queenslayer?"
Jaime did earn his reputation as "Kingslayer" by turning on the very king he was supposed to be guarding. But he did it for the greater good as the "Mad King" would have laid waste to all. So will Jaime sacrifice his love for the good of the world? Especially with Cersei planning something nefarious with the Golden Company who sound almost ass ruthless as the Dothraki themselves.
But if Jaime turns on Cersei, it would be a given that she won't show him any mercy. Game of Thrones is not known for its redemption moments. So don't expect to see Cersei repent her sins at her deathbed with Jaime weeping over her dying form. If Cersei Lannister were to go out, she would either go out in style or in a truly pathetic and satisfying way for the fans to enjoy. Remember Joffrey?
As things stand, it seems like the show is building up to a final showdown between the Lannister siblings for the fate of the kingdoms and we for one can't wait.