CECELIA
Cecelia [Cece for short] is your stereotypical posh kid rival, until that's sort of cut short by her being recruited to the team of magical girls. Carmen is, of course, a little upset by this initially, seeing as when it happens she's nothing but passively mean to him, but they get along soon enough.
GENDER
Cece is a trans girl that uses she/her. okay this ones fun,, she starts out like the sort of "bratty prep boy" archetype, but then she's chosen by the crystal, has her transformation... and is completely taken off guard by the magical girl transformation giving her a dress, having done no gender exploration beforehand. she at first is very shocked and confused, probably says something like "i'm not a girl tho??" [← clueless] but then Carmen is like "oh dang, i mean you can be a girl and stuff if you want but if you dont like the fit we can see what can be done about changing it" and cece is like "I Can Be A Girl If I Want????"
ARC
Cece essentially ends up leads this double life, exploring a reality that's kinder than she's ever known while transformed or with her team, while hiding her secret identity [and regular identity] while at school and at home. It turns out that she was the way she was because her parents and her social circles at the start of the story all pushed this narrative of suffering being necessary, of having to maintain a very specific image just because it's "normal." this leads to her gradually becoming kinder, softer, realizing that she doesn't need to suffer for no reason other than it being what "everybody does," because Carmen and the rest of the gang don't buy into any of that, and they're some of the nicest, happiest people she knows, so why can't she be that way too?