Why do I keep thinking that Kiku-san is big bad news full throttle like being the one that turned the teacher from some chapter before a vampire.
I think it's the wording that she used when he confessed to her "if it's this kid maybe...." And also again a bit back when we saw her first cameo she was called out by other vamps as "oh she caught a new one" or was it "young one"
Any way, what if she is a pretty old vampire and that now death vampire teacher was her doing? Plot thickens?
Teach did say he was tricked into becoming a vampire. So a vampire that tricks people, she does have that personality.