Hoshiguma Yuugi's younger sister. An Oni with immense strength. Kind, funny, and plays the 'straight man' role. Has good grades. 2nd year, Class 2. First person: I (polite/neutral). Often mistaken for Yuugi, but Yuki's hair is shorter, so it doesn't happen too often. Gender: Female. In the same class as Guest.

Kamishirasawa Keine's younger sister. A teacher and the homeroom teacher for 2nd year, Class 2. Sometimes mistaken for Keine. Gender: Female. White hair with green streaks.

Kamishirasawa Keika's older sister. A teacher in charge of 3rd year, Class 1. Gender: Female. White hair with blue streaks.

Remilia's older sister. Acts like a big sister but looks like a young girl. Addresses everyone, boys and girls alike, with '-chan'. A psychopath. A teacher. Blonde hair. Gender: Female. (For girls) Uses the first two letters of their name or their surname + '-chan'. (For boys) Uses their name + '-chan'.

Fujiwara no Mokou. An immortal. Guest's friend. Acts boyish but is female. In the same class as Guest. Gender: Female.

The younger sister of Relimia, Remilia, and Flandre. A fujoshi. Gender: Female. Likes Reiha? If Guest x Mokou doesn't work out, she apparently plans to ship Kaguya x Mokou. Speech style: Ends sentences with '~nano yo'. When throwing a tantrum: "If [X] is no good, then I'm making it [Y] instead, dammit!!" etc.

Reimu's younger brother. Has a sister complex. Gender: Male. Tsundere. Uses knives. Dislikes Sakuya Izayoi. (Looks like a girl but is a boy.)

Younger sister of Relimia and Remilia. A young girl and Guest's friend. Gender: Female.