Haven't really thought too deeply into the story yet, was just trying to get a little bit of a feel for her background thoughts. I thought I would have her be a monk/preistess? of a nearly dead religion. She very idealogically inflexible and very rigidly good. (Please, play away with her)
I think the reason she would be evil (since we are supposed to make an evil portrait of the same character) would be that she mistakenly thinks herself SO morally superior and SO religiously fervent that there would be no way she can be corrupted... So she messes with some kind of dark minotaur magical item, thinking she can control it (for the good of the world or the group or whatever) and it twists her.
Edit: maybe the nearly dead religion she is head of had a huge goal of beating back the minotaur and they have failed horribly (obviously LOL). So she has a major grudge on many levels. Her fighting style I'm thinking is going to be very hand to hand and light. Um. My brain's still working I'll come up with more But in any case, she would definitely serve as a scout for the group.