Biino Bando is a human character who joins the staff of the amusement park where the story takes place. Her employment is foreshadowed in a dream experienced by another character before she officially becomes part of the team to help address a shortage of workers. She is a high school student with a distinct appearance, characterized by short, straight chestnut-brown hair and a purple and yellow flower clip worn on the left side of her head. Her eyes are a notable red-brown color, and she is often seen in her school uniform.

Biino possesses a remarkably kind and cheerful personality. Her most defining trait is her intense determination, demonstrated vividly during her job interview. She arrives for this interview with a visible, bloody injury, having been stabbed by her elder brother who did not want her to work at the park. Despite the severity of the situation and the interview panel's immediate suggestion that she go to a hospital, Biino refuses to leave until she is hired. She maintains her cheerful smile even under these extreme circumstances and shows no resentment toward her brother for injuring her, even expressing concern for his well-being after he is subdued. Her motivation is a straightforward and earnest desire to secure the job, a goal she prioritizes above her own immediate need for medical care.

In the story, Biino's role is that of a new part-time employee at the park. After her dramatic hiring and subsequent trip to the hospital in an ambulance, she officially becomes a member of the staff. She is assigned to work at a shaved ice stand located near the pool area of the park. Her interactions with other characters are largely professional, but her unusual introduction creates a memorable dynamic with the park's managing staff, including the character who interviewed her. A notable recurring element associated with her character is a fascination with blood. This quirk manifests as a running gag, where situations involving her often reference blood, and she has even fervently suggested incorporating gore into the park's promotional materials.

Her development extends beyond her comedic introduction. A deeper exploration of her character reveals that the strange and violent incidents surrounding her are the result of a curse. This curse negatively influences the people around her, often causing them to become abusive or causing accidents to befall her. This background provides a more somber context for her brother's actions and explains her persistent optimism in the face of constant misfortune. The curse creates a pattern where she is frequently subjected to harm, yet her resolve and cheerful nature remain intact, though the constant pressure can cause her perkiness to wear thin. This tragic element contrasts with her surface-level role as a cheerful part-timer, adding a layer of complexity to her seemingly simple motivation to work at the park.