User blog comment:IamJakuhoRaikoben/Chapter 388: Erza vs. Minerva, Review./@comment-5303512-20140613080707/@comment-7418318-20140613122734

I'm not so sure about that.

Sure she was the one to willingly join a Dark Guild, but the transformation to a Demon was forced onto her without even the chance to resist. She seemed to enjoy the first moments after awakening, but that's all we know about her after she was changed.

Maybe existing as a Demon didn't turn out to be as great as it appeared the first few minutes.

For one thing she would never again be able to have any normal relationships. Just the semi-friendly relation between the Demons were anyone could stab her in the back at any moment for a promotion or just out of spite. If that slowly sank in, she's bound to have some reservations about wanting to live a Demon's life.