Moriuji Waka

Haru’s older sister.
With their parents out of town, she takes care of the cooking and cleaning, and the pair attend the same school.
While Waka is only one year older than Haru, she has adopted an air of resigned reliability in order to meet the expectations of the people around her.
Although she comes off as a polite honor-student type, she reveals a rather dark side towards those who get close to her brother, becoming the Demon Lord’s vessel.