
She would be a succubus, not incubus. Incubi are male while succube are female.
Honestly, though, it would make sense if she were, because why and how else would an angel have fallen so far from grace and be so fixated? It would also make sense as to why everyone is freaking out over her. An innocent succubus on her first mission. Lol. But, to throw a wrench into that theory, she's a little too goody two shoes, a little too naive and cute and everyone else has horns, but she doesn't. It would make more sense that the school is a place created to have nanami interact with big T so the angels could get him back. They bespelled it so they could force that outcome and threw in a bunch of minor demons and incubi to corrupt her afterwards so he leaves willingly--which seems to be the main objective here. But who the hell knows? This story gets weirder by the minute.

Yes, I know, thats why I said "wouldn't it make more sense for NANAMI(the boyfriend) to be the incubus, not being mean but read it before you write it
Side note, And he legit had horns, she comes from an ordinary family , and if you forgot the Angel woman said that she used petals or whatever to make her be like that, and after she has sex with nanami, asuma will be free from her

I gotcha. I completely got their names confused. I went from reading an update on another manga where the girl was nanami to this one and it threw me off. Sorry for the misunderstanding. I got everyone's names all jumbled. But yeah, it seems like her own personal sex hell of forgetfulness, doesn't it?
Tbh, I actually kind of understand the story but i feel like the foursome is unnecessary and annoying. I guess it was added just for fan service. Though i know it's because of the angle, it still makes her look like a slut.
( ̄へ ̄)