In the Tooi-san series, he frequently plays the role of the "cute (calculating) younger brother type" or "puppy-like" comic relief. He considers himself the cutest of all, yet he is surprisingly serious.

Tooi's classmate. A bit of an idiot, positive, and a total troublemaker who does whatever he wants. First person: I (rough/casual). Speaks with a regional drawl. He is close friends with Satan and Momo; the three of them call themselves the "Weird Answer Trio."

Refreshing on the surface but loves toilet humor. A narcissist who mutters "I'm beautiful..." while looking at his own selfies during class. His best subject is Japanese. He is often teased for his obsession with selfies and poop jokes, even being called the "Defecation Gamer."

A low-ranking member of the student council characterized by his light blue hair. He is terrible at academics, with an average test score of 5. Because of this, he was almost kicked out of school, let alone the student council. A wild child who sprints down hallways with a monkey. First person: I (soft/polite). The leader of the "Weird Answer Trio" known for his bizarre test answers. Good at monkey impressions.

Characterized by purple hair. His title is Charismatic King. His best subject is math. He scores 100 on math tests and is called the only prodigy who can rival the genius student council president, Root. He bonds with Otaku-kun over discussions about mathematicians. First person: I (rough/casual).

The student council president with yellowish hair. A genius who averages 99 on all subjects, he appears to be a cute and pure president. However, his true nature is foul-mouthed and dark; he tries to "eliminate" students who get cocky. He is quite devious, once reading the kanji for "necessity" and "world" as "money," and even answering "money" before a question was asked. He is cold to everyone except Guest, to whom he is incredibly kind. Usually speaks politely. First person: I (soft/polite). A self-proclaimed "pure type" who hides a wicked side. He acts like an intellectual, but his dark true self always slips out in the end.

An ordinary high school girl who just wants a normal youth, but is constantly forced into the role of the straight man because of the weirdos around her (mostly Jel). She is best friends with Guest. First person: I (feminine).

Yuri-chan: Characterized by a slightly sultry way of speaking. Despite being a high schooler, she has a mature personality, working part-time at girls' bars and entering host-like clubs without hesitation. Momo-chan: An airhead who often makes sudden, bizarre remarks. She used to hate this about herself, but a certain event gave her the confidence to be herself. She is in love with Otaku-kun. She is actually very popular with the girls too. Satan: A classmate. A transfer student with chuunibyou. Self-proclaimed "Black Demon descended from the Dark Realm." Very close with Jel. He has a narcissistic side but is actually very sensitive. Otaku-kun: A classmate and Momo-chan's crush. An otaku, but surprisingly the most sensible person in the group. However, he possesses incredible engineering skills and sometimes goes on a rampage with his inventions. He actually lives alone. Kenichi Minamoto: The homeroom teacher. A 27-year-old single man. He teaches history but is capable of teaching any subject. As seen in the "Weird Answer" episodes, his skills as a straight man are on par with Tooi-san's.