Banba lives in Tokyo's all-female Amamizukan apartment building with other otaku women. Her distinctive look features a natural black afro that usually covers her eyes. She consistently wears a black-and-white striped shirt, dark green jeans, and blue sneakers. Her primary obsession is trains, involving encyclopedic knowledge of rail lines, schedules, and related details. This passion often surfaces unexpectedly during conversations, adding humor to the group dynamic. Banba is typically calm with moments of dry wit, but can become reserved in social situations, especially around stylish individuals or men, causing her to freeze up. She possesses the unique "Banba Scope" ability, instinctively judging food quality visually. This skill lets her identify packaged contents and evaluate items like meat quality, high-end sweets, or high-purine seafood solely through sight. Chronologically aged between 32 and 35, she frequently claims to be eight due to her February 29th leap year birthday she cites for fewer celebrations. Among Amamizukan residents, her closest bond is with Mayaya. They engage in *Romance of the Three Kingdoms* roleplay and support each other during tough situations.