Mutsumi Onigami holds the position of eldest sister and head of the Onigami household. She manages domestic duties and provides essential stability for her younger sisters, Mei and Hazuki. Her practical approach governs household management, encompassing finances and daily routines. This leadership extends to decisions about supernatural visitors: she permitted the initial round creature a temporary stay and later negotiated living arrangements for Jigoku-san and the Chimimoryo spirits within the gardening shed. Mutsumi exhibits responsibility through managing household expenses and resolving conflicts between her sisters. She demonstrates notable adaptability when faced with supernatural events, including the arrival of twelve Chimimo creatures and their master from Hell. Her strategy involves integrating these beings into existing household routines instead of outright rejection. She actively maintains order during chaotic situations, such as when the Chimimo creatures create portals or Jigoku-san attempts to cause havoc. Mutsumi navigates these disturbances with a focus on preserving normalcy and family harmony. Her physical characteristics include multicolored hair, frequently appearing blonde or yellow, and a mature appearance befitting her role as an adult caregiver. She typically wears practical clothing like long skirts, sandals, and socks. Information regarding Mutsumi's background history, specific age, occupation, or personal history outside her household role remains unavailable. Her character development throughout the series remains outside the documented narrative scope.