Tsuchimikado Maika

Japanese name:

土御門 舞夏

Motoharu's younger step sister. She wears a maid attire as she goes to a Maid School to learn to become a Maid and rides on top of a cleaning bot. She has a friendly relationship with Touma and knows that he has two girls (Index and Aisa) living with him but keeps it a secret except to Tōma himself. Even though she lives in her schools dormitory, she sometimes go to live at her brother's apartment.

Seiyuu: Fukuen Misato

Wikipedia