Ruriko

Sumi's maid. A lovely young woman that always wears a calm smile yet she is very strict when it comes to Sumi's studies; often hitting her upside the head with a slipper to wake her up. She has a keen eye, not fooled when Sumi changed into her magical form. Yet even though she is hard on Sumi and not afraid to point out her master's faults, she acts like an older sister. She is very friendly to Ink and refers to Sumi as Oujosama.

(Wikipedia)