A young man who behaves like a jester and a ringmaster.
Within his body dwell two beings: "Fumiya" and "Aiga."
His first-person pronoun constantly switches between "ore" and "boku," and the differences between the two seep into his words and actions.

A humanoid inorganic being raised in a showhouse that combined an amusement park and a casino.
Because he is not human, his origins and the very structure of his body are shrouded in mystery.
He currently spends his days as a member of the library club, but he perceives the "outside world" as something somehow alien. His surname is written as "五月七日" and read as "Tsuyuri." His hobbies are researching torture, torment, and hell; he is an anti-intellectualist who seeks pleasure. His birthday is January 8th.

A young man who grew up in a poor household but speaks like a refined young lady.
Although his upbringing was far from affluent, his manner of speech alone is thoroughly that of a proper lady.
He is a member of the same library club as Yoji and is around high school age. His birthday is September 20th. His hobbies are related to modernism, Britain, and 1900s America.

A cheerful mood maker, but his true nature is that of a condescending, approval-seeking narcissist who craves attention. He loves fashion and trends, loves to flatter, and even pays attention to things others don't notice, though he also has a side that worries too much.

A hardworking, unremarkable, unpopular, ordinary-type guy. He has a complicated history with Kyoka Izumi and Koyo Ozaki, so he keeps his distance from them. Perhaps because he is bothered by it, his personality is somewhat warped. He denies that he could possibly have any complexes. But in truth...?