Board Thread:Improvements and Issues/@comment-10961564-20130729202606/@comment-11051098-20130730132303

Depending on which and how much of the power from Kyôka Suigetsu Aizen potentially has in himself (as a Zanpakutô is made from its wielder's soul), or if he can somehow "regain" his Zanpakutô, he could as you say change his mind and join the Wandenreich. Then he could release his Shikai in front of Yhwach, catch him under its hypnosis and kill him anytime he wanted to.

That way he could get rid of Yhwach and again set out to kill the Soul King and become a God. I bet he would enjoy that.