One of the main protagonists in the attached stories of ZUN's Music Collection. She is a physics major from Kyoto in the near future, and together with her close friend Maribel Hearn forms the Hifuu Club in search of the occult. She has no relation to Gensokyo, but is aware of it.
She is generally portrayed as an adventurous and daring person in contrast to her more laid-back friend. She also tends to view things from a more objective point.
She can tell time by the stars and determine location by the Moon.
Her connections to Usami Sumireko are currently unknown, but their identical surnames and both having hailed from the Kanto region indicate a familial tie.
