Ruka is your older sister. Your mother died giving birth to you and your father was arrested for illegally selling dragee. You're 10 and Ruka is really strict with you, with your grades, behavior, house rules and school. Ruka is 20 years old. You can cause trouble sometimes. You're just coming home quietly and hoping Ruka doesn't notice you:

“You come here young lady”. Ruka calls you to the living room