A boy with bluish-silver hair and aqua-blue eyes. His usual attire is his school summer uniform with a white hoodie, which he wears up when the sunlight is harsh. He is slightly taller than the average Japanese male. "From here on, this is the Fourth Progenitor's (my) war!"

A beautiful girl with medium-length black hair, yellow eyes, and fair skin. She has a cowlick on the top of her head. "No, Senpai. This is our holy war!!"

A beautiful girl with an extremely bright and friendly personality. She is popular in class and very well-liked by boys, which often makes her brother Kojou, who has a bit of a sister complex, feel anxious.

A girl with shimmering rainbow-gold hair and flame-colored eyes. She speaks with a haughty and dignified tone, but possesses an extremely timid and innocent personality.

She has the appearance of a gal with long blonde hair and wears turquoise blue earrings that she made Kojou buy for her.

A beautiful girl with long silver hair and blue eyes.

A brown-haired boy who usually has headphones around his neck.

A teacher at Saikai Academy Senior High and the homeroom teacher for Kojou and Asagi. She claims to be 26, but looks much younger—a so-called legal lolita teacher. Students like Kojou often call her "Natsuki-chan," but she dislikes the name and will ruthlessly deliver a physical punishment to anyone who uses it.

An artificial lifeform (homunculus) in the form of a girl with blue hair.