Kuguru Sahara is a half-Kappa navigating a human school environment populated by other races based on Japanese yōkai mythology. Her Kappa heritage grants her distinct physical traits and abilities, including exceptional swimming speed surpassing humans and significant physical strength.

Her headstrong personality stems from a family background involved in Kappa mobster activities. She has a younger sister, Chochomaru Sahara, who is a full Kappa. Initially, Chochomaru held hostile intentions towards Kuguru, believing their family required only one heir and attempting to eliminate her—a conflict rooted in interspecies dynamics within their family structure. The sisters later reconciled and restored their relationship to good terms.

Within the school setting, Kuguru develops romantic feelings for her human classmate, Shingo Oohashi, who demonstrates acceptance towards the specified races. This interpersonal dynamic unfolds against the backdrop of broader societal themes exploring coexistence and prejudice between humans and specified races.