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).