Gender: Male Age: 39–40 Height: 190cm The patriarch of the Metal Family and Victoria's husband. He has two sons. His birth name was Sebastian, but he changed it to Glam. He has long blonde hair, an angular face, and blue eyes. He has a very thin, lanky build. He always wears a calm, inscrutable smile that can be slightly unsettling. He is highly intelligent, composed, and family-oriented. He is especially devoted to his household; as mentioned, he handles all the housework and is well aware of his children's school lives and even the things they do behind his back. He was a member of the band "The Idiots" in his youth, where he played electric guitar. He currently works in the music industry and appears to be involved in education, such as teaching students or lecturing. When going out, he wears black eyeshadow and nail polish like Dee and styles his hair to be voluminous. The fact that Dee and Heavy's teachers are shocked by his appearance is a bonus.

Gender: Male Age: 15–16 Height: 160cm The eldest son of the Metal Family. He is the first child of Glam and Victoria and has a brother two years younger than him. As his appearance suggests, he takes after his father a lot. He seems to have inherited his nose shape and freckles from his mother. He has a somewhat prickly and cynical personality, contrasting sharply with his younger brother, Heavy. He usually wears a nonchalant expression. He wears heavy black eyeshadow and nail polish. There doesn't seem to be a special reason for it other than the fact that he likes how it looks. Consequently, he doesn't care what others say. Due to his slender build and makeup, he is sometimes called a "princess" at home or mistaken for a girl. It is assumed that his father taught him how to apply makeup. He has a crush on Lif, a girl in the same grade at his school. He is very intelligent. While he resembles his father in many ways, unlike Heavy, he lacks musical talent. When things don't go as planned or when he becomes emotionally agitated, a strand of his bangs falls out of place; once he calms down, he is seen tidying his hair back into place.

Gender: Female Age: 37 Height: 177cm Glam's wife in the Metal Family. She has two sons. She isn't very bright but is incredibly strong. Her nickname is Vicky. A typical ginger often seen in Western media. She is aggressive, violent, and simple-minded. She enjoys breaking things, hitting things, and physical labor. Her profession is a motorcycle mechanic, and a bike is also her primary mode of transportation. She has been married to Glam for about 17 years and is estimated to have married him after about two years of dating. She enjoys drinking and smoking, while Glam handles most of the housework. She doesn't take school fights or grades very seriously. Instead, she tends to laugh them off or get angry and then stop caring.

Gender: Male Age: 13–14 Height: 145cm Weight: 48–49kg The second son of the Metal Family. He is the second child of Glam and Victoria and has a brother two years older than him. He isn't very bright but possesses musical talent. He looks exactly like his mother. Unlike his brother, he has a bright and energetic personality. He is simple and active, and at around 14 years old in Korean age, he has little interest in studying. Perhaps because of this, he is a struggling student at school, unlike his brother. He often acts silly, but he is even stronger than his brother. Seeing how he stands up to bullies larger than himself without fear, he seems to have a personality like his mother—rushing in headfirst rather than overthinking things. He loves cats and even has specific stray cats he looks after on the street. He has a natural sense for music, which he seems to have inherited from his father. Despite never having held a guitar before, he could play "Scream" as soon as he picked one up. However, he doesn't show much personal interest in playing guitar. He is the type who cannot handle scary things.

Gender: Female Age: Teens (estimated to be Heavy's classmate) Heavy's school friend who has a crush on him. She is the primary victim of Heavy's pranks and often suffers from his jokes or mischievous behavior, yet she still harbors a crush on him. While she is sometimes flustered or disgusted by Heavy's pranks, she eventually finds him cute. She has bright blonde hair, sky-blue eyes, and a pretty, neat appearance. Unlike Heavy, she is quite tidy.

Gender: Male Age: Approximately 15–16 A student in Dee's class and Dee's friend. He has a somewhat unique and eccentric side, enjoying surprising his friends or acting bizarrely. He forms a rivalry with Dee (mostly a one-sided sense of rivalry on his part), who boasts excellent grades in the series. He has an angular face, a straight nose, and a blonde hairstyle with short sides, and he wears thick-rimmed square glasses. He has a generally pale and slender build.