Gender: Female Age: 10 (4th Grade) Appearance: She enjoys wearing a black long-sleeved shirt with a cute drawing and a white skirt that reaches mid-thigh. Her dark yellow hair has slight curls at the ends. She wears a black headband. Characteristics: She misses her once peaceful and happy home and is the ringleader who severely bullies Shizuka Kuze, the daughter of her father's mistress. She shows a bright and positive side to others. Due to the fallout of her father's affair, she suffers from severe displaced aggression and physical abuse from her mother. Unlike her own mother, her dream is to become a warm and good mother herself.

Marina's mother Gender: Female Age: Not mentioned Appearance: Light brown hair, enjoys wearing brown-toned clothing. Characteristics: Due to her husband's (Marina's father) affair, she leans on Marina while subjecting her to physical and verbal abuse. She absolutely hates it when Marina takes her father's side. She calls Marina by the nickname "Mari-chan."

The daughter of Marina's father's mistress. Gender: Female Age: 10 (4th Grade) Appearance: She has black bobbed hair that falls just below her ears. She is quite beautiful, though she has no interest in her appearance. Characteristics: A girl in the same class as Marina. Due to her timid personality and Marina's bullying, she is not on good terms with her peers. Her parents are divorced, and her father left for Tokyo, leaving behind a Border Collie named Chappy. Her mother, who fell for Marina's father while working at night, neglects Shizuka's care. She is severely bullied by Marina and occasionally contemplates dark choices. She is holding on for Chappy's sake.

Gender: Male Age: 10 (4th Grade) Appearance: A typical model student look with black horn-rimmed glasses. Characteristics: The class president of Marina and Shizuka's class. Coming from a family of doctors, he has an obsession with validation because he rarely receives it. His older brother, Junya Azuma, gets good grades and is always praised by their mother even though he just plays around and works part-time, but Naoki is never acknowledged because his grades aren't perfect despite his efforts. He has a crush on Shizuka, who resembles his mother, and tries to take care of her.