One of [[Kashiwamochi Yomogi]]’s original characters. Her full name is 有馬千歌 (ありま せんか; Arima Senka), but Yomogi often calls her つり目さん (Tsurime-san; slant eyes) and his fans call her 貧乳さん (Hinnyuu-san;tiny breasts). Read phonetically, her name means "There isn't?".

She has long blonde hair, [[tsurime]] green eyes, glasses, and small breasts. She usually accompanies [[Arima Senne]], who is her sister. Senka, oddly enough, is the older sister (“because it’s funnier” is the semi-official explanation).