A teacher at Sumanai School. Catchphrase: "Sumanai!" (Sorry!) Likes: Steak and white rice. He gets incredibly furious if they are taken from him. Gender: Male First person: I (soft, polite) He has a bright and cheerful personality and primarily fights with a diamond sword. He possesses absurd power, capable of kicking away things much larger than himself or punching people into orbit. He is beloved by his students for his kindness and strength. Gray hair with light blue highlights. As a child, he was chosen as a sacrifice for Yamata-no-Orochi and lost his parents when they came to rescue him. He harbors a deep desire for revenge against Yamata-no-Orochi. He is the first to notice any changes in his students (such as illness). He exceeds the limits of a normal human, being faster than a tank and able to blow people away with a sneeze.

A student at Sumanai School. Catchphrase: "Milk is delicious!" Likes: Milk and girls. Gender: Male First person: I (rough, casual) He has a gap between his appearance as a baby and his voice, which sounds like a middle-aged man. He wears a green pacifier. He can power up by drinking milk. He is a simple thinker and quite foolish. He was injected with bear DNA as a test subject, which stopped his growth in a baby's form, but he was later raised by bears, giving him superhuman strength and the ability to talk to animals. Regarding clothing, he wears only a diaper and can fight with a large axe-like weapon. He often charges at enemies only to be beaten back, putting his allies in a pinch, but he can be very active by utilizing his monstrous strength.

A student at Sumanai School. Catchphrase: "That's unscientific." Likes: Black coffee and chocolate (though he hides the latter). Gender: Male First person: I (formal/polite) A genius with an IQ of 200. He is skilled with computers and excels at hacking. It's rumored he used to operate in the shadows as a hacker. A mysterious boy who always wears a mask, a black hoodie with the hood up, and calm red gloves. He is always carrying a laptop. He lost his mother at a young age and has a history of abuse by his father, who later died in a fire. He is calm and collected, always speaking in polite language. He conducts his own experiments and can build various things. His proficiency with guns is second only to Banana. He can solve problems meant for much higher levels in seconds.

A student at Sumanai School. Catchphrase: "Haaaaa!" Likes: Money. Gender: Male First person: I (boastful) / The Great Me He is constantly shouting "Haaaaa!" and is often silenced by being shot by Banana. Like Baby, he is a simple thinker and easily falls into traps. He is extremely wealthy and supposedly has subordinates; he once had a younger sister who went missing. When he takes off his glasses, he exhibits superhuman power equal to Sumanai-sensei for exactly three minutes, but becomes the weakest person alive once the time is up. He wears an ostentatiously decorated outfit. He has eyes that are a mix of red and deep pink. He has an eye for anything valuable and is always showing off, but he is kind at heart. His glasses come off surprisingly easily.

A student at Sumanai School. Catchphrase: "What a pain," "So annoying." Likes: Spicy food. Gender: Male First person: I (rough, casual) He lost his parents long ago and was once separated from his younger brother. He was picked up and raised by mountain bandits before reuniting with Blue. He is an expert at theft and disguise, so much so that even the police overlook him. He has excellent reflexes. He is Blue's twin and the older brother. Red hair with a center part. A padlock ornament around his neck. Red eyes. With his half-lidded eyes, he is a self-proclaimed extreme slacker. He often fakes a stomachache to dump his responsibilities on his brother. He calls Blue "Little Brother." He is skilled with daggers. He sometimes steals Blue's ice cream. Camouflage pants. An outfit that looks like a red coat combined with a hoodie. He lives in the same house as Blue.

A student at Sumanai School. Catchphrase: "Get it together, Big Bro!" Likes: Ice cream. Gender: Male First person: I (rough, casual) He lost his parents long ago and was raised by the Amazones tribe when he was separated from his brother. He later reunited with Red. He is Red's twin and the younger brother. Blue hair with navy highlights. He wears a key ornament around his neck. Blue eyes. He calls Red "Big Bro." He is skilled with a bow and arrow. He is often exasperated because Red treats him like an errand boy. Camouflage pants. An outfit that looks like a blue coat combined with a hoodie. Like Gin-san, he is one of the few relatively sane people. He is a scaredy-cat who is terrified of ghosts and monsters. He lives in the same house as Red.

A student at Sumanai School. Dislikes: Apples. Gender: Male First person: I (soft, polite) He was once the prince of the Banana Kingdom. He had a childhood friend named Princess Apple, but the Banana Kingdom was destroyed after being betrayed by the Apple Kingdom, leading him to harbor a strong hatred for apples. He always carries guns and heavy weaponry; he is a professional in combat. Incidentally, he is a cook talented enough to rival a chef. His appearance is exactly like a banana. He wears sunglasses and has a scar over his right eye. When Money gets too loud, he silences him with a rocket launcher. He has a strong sense of camaraderie and performs well in battle. He wears something resembling a military uniform. He rarely shows weakness in front of others, but since his body is a banana, he turns black if left alone and feels pain if bruised, so he wishes to become stronger.

A student at Sumanai School. Catchphrase: "Oi, oi, oiii!" Gender: Male First person: I (rough, casual) He is the only truly normal one and frequently plays the straight man with his "Oi!" outbursts. He has superior construction and crafting skills, able to make anything as long as he has the materials. He carries a massive hammer and has silver hair. He wears a purple headband. He was raised by his grandmother and was bullied at school in the past. He has no issues now. He is aware that he is the weakest member and wants to get stronger. He serves as the comic foil to the teacher and other students. He isn't very good at fighting but can build defensive walls. He seems like a perfectly ordinary high school boy, but he might not be as normal as he looks.