User blog comment:B214/Light Novel Volume 16 spoilers/@comment-9339850-20131020192040/@comment-9339850-20131021064130

hmmm, ok heres a far out theory.. What if Rizevim is actually after the Chichigami's power like we all are saying, and eventually actually succeeds but Issei, being the Shounen male hero that he is, he is able to defeat Rizevim and in the process absorbs the power of the Chichigami and becomes one (only for a short while, while the next true Chichigami is chosen).

Wow i cant believe i just came up with this insane plot line