User blog comment:TheCarrotSaysYumYum/Dragons, People and Demons.../@comment-288216-20120722054256

Nice theory.

Anyway, it's a BIG theory and might not be 100% true, but one point caught my attention: Mavis being friends of Zeref and Lumen Histoire being Zeref's power which Mavis sealed away. That might actually be true, who knows xD