Tani Kasumi (谷かすみ) was the 18 year old daughter of the owners of Kasumi Sou, a small wooden apartment building. Her room was facing Kazuya's room, and there was even a ladder connecting Kasumi and Kazuya's rooms.

Kasumi was also a coach for the local little league baseball team, and her uniform number was 33. She was very active, and called herself "boku" (male form of I). Kasumi was very tomboy-ish, but she also had a very kind side.

Kasumi's voice is done by Takahashi Mikako (高橋美佳子) .