Talk:Original Sin Story: Complete Edition/@comment-119.95.137.235-20150815013428/@comment-146.113.79.217-20160217145131

It was confirmed in the ending of the Gift from the Princess Who Brought Sleep novel wherein she (inside the Clockworker's Doll) and Elluka discussed the fact that she took on those character's identities and hypnotized herself (and everyone else) into believing she was them using her magic.

It was never a "theory" that got confirmed it was an actual plot twist in the novel that went well remarked upon for over a year. I'd suggest reading up on Margarita, Eve, or the Gift novel articles to get more pertinent information on it.