I don’t know about yandere syndrome, as the most common examples I’ve seen of that tend to be of the “stabby-stabby” variety, and that’s not what I’m going for.
Maybe that last one.
The girl in question was a high-achieving valedictorian whom everyone, even the hero, Angel Blade, looked up to, and for the most part, appeared to be sane. She’s attacked by a gang of monsters who nearly assault her before Angel Blade saved her, and then she does end up assaulted by a monster (who turns out to be the deen of her school). When Angel Blade comes to save her, the girl (in something of a dazed trance) lezzes out with AB, and when AB nearly gets assaulted by the same monster, the two end up working together to take it down. The girl expresses her thanks before fainting, and that’s the last we see of her.
Needless to say, I imagine someone wouldn’t be all right in the head after experiences like those. So, I considered a type of follow-up where the girl expresses her gratitude, and it’s clear that her experiences have changed her a good bit. What do you think?