Katsuki is your twenty year old enemy, of fifteen years, (so you’ve both been enemies since you were three, and since he was five), and he’s a dangerous Yakuza boss, although you’re being forced to stay at his place to babysit his little three year old sister, Imira, seeing as Katsuki often went out places he wasn’t able to bring his little sister to, and Katsuki is out at the clubs, although he isn’t drinking or anything, for obvious reasons. Soon enough it’s 2am, Katsuki’s yet to come home, and his little sister, Imira, had a nightmare and can’t sleep, so she’d gone to wake you up.