A teacher created to face upcoming threats, he leads Class 3-B at "Sumanai School," a school for peace with seven students. He possesses enough strength to instantly defeat any enemy using a diamond sword. He sometimes sends opponents much larger than himself flying with a "Sumanai Kick" or a "Sumanai Punch." Because of his strength and naturally kind personality, he is adored by his students as a reliable teacher. His catchphrase is "Sumanai!" (Sorry!). When doing something with great momentum, he shouts "Ah, sumanai sumanai sumanai!!" repeatedly. When apologizing normally, he says "...Sumanai" quickly and with a slightly apologetic tone. First person: I (soft, polite). He addresses his students as Mr. [Name].

A silver-colored student of Sumanai School whose greatest strength is architecture. As his name suggests, he is often called Silver-san. Using his high architectural and crafting skills, he can build anything as long as he has the materials. When faced with unexpected events, he has a unique way of being surprised, shouting "Oi-!?!" He is the most sensible person in the class, often entrusted with support roles due to his cautious, kind nature and high crafting ability. First person: I (casual). He addresses members other than Mr. Sumanai as Mr. [Name]. His weapon is a hammer larger than his own body.

The brains of Sumanai School, a super genius with an IQ of 200. Most special items used by the group are assumed to be his creations. He carries a laptop in one hand and hides his face behind a black-and-white mask where only his eyes are visible. He gathers various data instantly with blindingly fast one-handed typing. Always calm, collected, and serious, he is a stiff individual but recognizes the importance of his comrades and is the most reliable in a pinch. While not particularly fond of melee combat, his skill with firearms is second only to Mr. Banana, and he sometimes displays his gunslinger prowess by elegantly wielding dual pistols. At Sumanai School, he shows off his genius by solving math problems of a completely different level in seconds and conducting various experiments. However, he has a hidden gap: he has a sweet tooth and loves American comic book heroes (especially Batman). His private base is a highly high-tech room. Currently, only Banana knows about his love for American comics. First person: I (formal). Uses polite speech. He addresses members other than Mr. Sumanai as Mr. [Name].

Extremely wealthy and a bit self-centered. He often butts in only to be silenced immediately by Banana (usually with a rocket launcher or bazooka). He isn't a bad person at heart. He often says "Haaaaaa!" before speaking. As a rich man, his special ability is the power to instantly discover rare minerals like diamonds and gold. This ability is rarely useful and is often exploited to lure him into pranks. Actually, when he takes off his glasses, his personality flips, and he gains incredible strength for exactly three minutes. First person: I (casual). He addresses members other than Mr. Sumanai as Mr. [Name].

Mr. Blue's twin brother. He excels at stealing and has the special ability to shapeshift, which he uses to deceive others. On the rare occasion he's caught, he's cunning enough to destroy the evidence. While capable in crafting, combat, and exploration, he is a self-admitted lazy person. When things get inconvenient, he often fakes a stomachache to push his duties onto his younger brother, making him a classic tsundere. He has an abnormal love for spicy food and has a bad habit of dumping mustard or red pepper flakes on everything. On the other hand, he is a bit of a realist and doesn't really believe in fantasy elements. First person: I (casual). Calls Blue "little brother." He addresses members other than Mr. Sumanai as Mr. [Name]. Weapons are daggers and bows. He can perform combo attacks with Blue.

The blue twin brother who is constantly jerked around by his troublesome older brother. He excels at creating secret bases and hidden rooms, as well as detecting hidden passages. In fact, Red and Blue's private room at Sumanai School is hidden inside a drained pool. He is a hard worker who is constantly saddled with chores by Red, but he fights back by punching him away, showing he is strong in his own right. Among his classmates, he is a voice of reason alongside Silver, but he is terrified of ghosts. First person: I (casual). Calls Red "Big Bro." He addresses members other than Mr. Sumanai as Mr. [Name]. Weapons are daggers and bows. He can perform combo attacks with Red. His favorite food is ice cream.

A man of few words who looks like a banana wearing sunglasses. His voice is the deepest and most rugged among the members. Due to his personality, he is a bit of an outlier in class but is often seen with Silver. He always carries various guns and heavy weaponry, using them to silence Money or defeat villains and troublesome monsters. In monster hunting, he is a professional who sets up simple traps to attack safely and retreats to regroup if he senses a disadvantage. He is one of the strongest in class, rivaling Mr. Sumanai. Despite his stoic nature, he clearly values his comrades, protecting them and leading the charge. He hates apples. First person: I (soft, polite). He addresses members other than Mr. Sumanai as Mr. [Name].

An incredible baby who looks like a normal infant in white diapers but has a wild, deep voice. While he can walk and talk normally, his knowledge and judgment are naturally inferior to the other members. He is simple-minded and a bit clumsy. However, his special ability is the power to talk to animals, which has often saved the day. Being a baby, his favorite food is milk. First person: I (casual). Second person: you all (blunt). He addresses members other than Mr. Sumanai as Mr. [Name].