An original character Yomogi often draws. Her full name is 有馬千音 (ありま せんね; Arima Senne), but Yomogi often call her 乳眼鏡さん (Chichimegane-san; breasts and glasses). Phonetically read, her name means "There isn't, is there?".
Senne has long auburn hair, red eyes, glasses, a mole on her right breast near the nipple and a curly ahoge. Although, in some of Yomogi's early art of her, she is lacking some of these traits.
She is the younger sister of another character, Arima Senka.