Marimo Bandō is a second-year student at Kameido High School and a core member of the school's tennis club, which serves as the central group for the series. She is one of four main characters whose everyday lives are filled with absurd and rapid-fire comedy. Standing 169 cm tall and weighing 58 kg, she is characterized by long blue hair and blue eyes. Her understanding of the world is notably warped, leading to a large number of misconceptions that frequently drive her actions. This results in antics that are both bizarre and often unlawful, such as wearing and eating another girl's underwear or kidnapping a child. Despite her lack of maturity and poor self-control, she possesses a kind-hearted nature beneath her chaotic exterior. Her motivations are rarely serious; she simply follows her impulses and the whims of the group, contributing to the series' nonsensical plotlines. In the story, she functions as a primary source of trouble and unpredictability, often dragging her friends into dangerous or strange situations. Her key relationships include fellow club members Kanae Shinjo, Nasuno Takamiya, and Yuri Oshimoto, with whom she shares a dynamic of mutual exasperation and camaraderie. She also forms a close bond with Tomarin, an alien who crash-lands on Earth and becomes her roommate and friend. Marimo experiences little to no character development over the course of the series, remaining consistently eccentric and prone to bizarre behavior. Her notable abilities are not athletic or intellectual but lie in her capacity for causing chaos through her misguided actions and fearless approach to whatever scenario the group encounters.