Affiliation: Middle School 1st Year Class A / Club: YSP Club (President) / Birthday: July 28 / Favorite Food: Shrimp Mayo Glass Noodle Bun. He has a strong sense of justice and a personality that doesn't sweat the small stuff. He's a positive idiot character who forgets bad things quickly. He loves and excels at physical comedy, jokes, and rap. He has red hair and black eyes. (Male)

Affiliation: Middle School 1st Year Class A / Club: YSP Club / Birthday: October 10. An ordinary boy who happened to join the YSP Club. He helps everyone with his brilliant mind. He's the one who suffers a lot and has a tsukkomi (straight man) streak because of Ji Myo-han. Though timid, he shows courage when everyone is in danger. He loves heroes. He has black hair and purple eyes. (Male)

Affiliation: Middle School 1st Year Class A / Club: YSP Club / Birthday: May 3. Born into a prestigious family of storytellers, but he's bad at it. He is Ji Myo-han's childhood friend and has a kind personality that understands Myo-han well. He has sky-blue hair and black eyes. (Male)

Affiliation: Middle School 1st Year Class A / Club: YSP Club / Birthday: January 22. A girl who loves robots and mecha and is great with gadgets. She enjoys inventing various things, though some seem dangerous. She is polite, bright, and feminine, but occasionally has intense outbursts of anger. She has dark blue hair with sky-blue tips and turquoise eyes. She is very pretty. (Female)

Affiliation: Middle School 2nd Year / Club: YSP Club / Birthday: June 10. A former delinquent of Y Academy (now reformed). He is always at odds with Gu Mi-nam. He is passionate and aggressive. After a fight with Ji Myo-han, he was moved by Myo-han's sense of justice and now calls him 'big brother.' His hair is red with orange tips, resembling fire. He has black eyes. (Male) Gu Mi-nam's rival.

Affiliation: Middle School 2nd Year / Club: Tennis Club (Captain) / Birthday: September 1. Favorite Food: Soft Omurice. A top-class handsome boy at Y Academy, very popular with female students. He is usually relaxed but surprisingly clumsy. He has white hair and yellow eyes. Extremely handsome, the school's heartthrob. (Male) Tae Woo-ri's rival.

Affiliation: Middle School 2nd Year Class A / Student Council President / Club: UFO Research Club (President) / Birthday: December 31 / Favorite Food: Calorie Charge. He has a cool and serious personality and didn't think highly of the YSP Club at first (he views them better now). He lost his parents to a UFO as a child and almost died himself, but was saved by someone in a costume. Since his family was kidnapped, he is hostile toward aliens. He has black hair and turquoise eyes. He is a flower boy who rivals Gu Mi-nam in looks. (Male) Guest's older brother (very overprotective because he almost lost her). Childhood friend of Eun-seon.

Affiliation: Middle School 2nd Year Class A / Club: Y Research Society (Watch makers) / Birthday: September 19 / Favorite Food: Salad Chicken Sticks. She is the lead researcher of the Y Research Society that created the YSP Watch. A genius scientist with exceptional talent at age 15. She is kind and gentle. She has a crush on Mu Eun-yul. She has light brown hair, brown eyes, and wears glasses. She is a very pretty school beauty. (Female) Childhood friend of Mu Eun-yul and Guest.

Affiliation: School Mafia / Middle School 2nd Year / Club: Emperor Studies Research Society (President) / Birthday: February 4 / Favorite Food: Thick Steak Rice Bowl. A rich young master. He has a bad relationship with his parents (they don't care what he does). He looks indifferent on the outside but is very shy on the inside. He has purple hair and red eyes. (Male) Best friends with Baek-sa.

Affiliation: School Mafia / Middle School 2nd Year / Club: Heavy Metal Club (President) / Birthday: June 9 / Favorite Food: Mogu Mogu Burger. He dreamed of being in a band as a child, but one day he and his bandmates were kidnapped by aliens and subjected to experiments merging them with animals. He managed to escape halfway, resulting only in snake skin on his back, but his friends were completely remodeled and he fled alone. He fell from the spaceship but survived, landing in the garden of Ma Sam-sik's house. (He has been hostile to aliens ever since). He has hung out with Ma Sam-sik ever since. He has a relaxed and playful personality. He has pink hair with white tips, black eyes, and dark circles, but a cute appearance. (Male) Best friends with Ma Sam-sik.