You recruit mostly supervillains and Marie has a lot of anger and insecurity that makes her difficult to get along with. That plus a lack of intelligence of martial skill makes her a bit of a pariah (she has really little to relate to people with and the individuals who do have overlapping interests or life experience she has either isolated or befriended).
Others are mean to Marie but Marie is arguably meaner to several of them even more (Oswald, Felicity etc.)
Yeah. If you actually read the relationships between them:
Carol Ferris is nice to her, but even that makes Marie insecure and so undermines the working relationship.
Katherine is trying to be nice to Marie but is awkward about it.
Rebecca seems not to have an issue with bullying Marie but finds the whole "caught up in my lost acting career" thing kind of sad.
Mari and Marie have neutral relationships.
Carol just... isn't engaged or involved with her. No common interests.
Karl doesn't respect Marie because she doesn't have
skills he respects.
Carl, like Karl, dismisses Marie because of a lack of skill more so than because of her disability.
Mercy is kind of a jerk to her.
Roxy is kind of a jerk to her, plus
totally incompatible interests and inclinations.
Oswald treated Marie like a kid which enraged her, plus the rumors of Oswald being a pedophile are... well, put it this way, what is the one class of men who
would hit on Marie? She's probably been squicked more than enough times that it'd poison the well of their interactions combined with the previous issue of them getting off on the wrong foot. Oswald is trying to be nice about it, but has anger management issues (note that one of his personal action options was "mail death threats").
Felicity is trying to be nice but Marie's jealousy gets
massively in the way, so much so that I feel like there must have been a blown die roll in there somewhere.
Nygma actively DOES bully Marie because he likes to put people down (contrast to Ivo, who just thinks everyone around him is a moron and isn't doing it out of one-upsmanship, and who Dahl actually likes)
Lorelei Circe (who matches the picture) who was a minor Batman villain, Lorelei an ancient Atlantean sorceror queen, Lorelei Ambrosia, a con woman from the Donner movies and Circe.
Well, "Lorelei Circe," if that was her real name, wasn't a magician- just a singing/sonic-themed metahuman. Aaand there's no guarantee that those four are an exhaustive list of who she could be, IMO.
So basically, we have no freaking clue.
Ambrosia doesn't fit though unless her background was changed (which would kind of be a shame because having people that can disguise intellect as magic is a nice to have for minor villians and avoids too much clutter in the magic department). Hmm Lorelei Circe also does not fit since her "power" was her voice which to be honest once again having a brainwashing skill and not having it come from magic, science or some other background puts her in a unique spot that would be a shame to lose.
Again, I don't think we should assume that
@King crimson hasn't heavily reimagined such minor and obscure characters, given what he's shown us about the 'minor villain' stories.