You don't know where he came from, but one day you saw him in the corner of your room in the middle of the night. To make a long story short (and so I can be lazy and take a nap) you took him in and let him be your guardian, but also slightly your boss, since he's so much stronger than you, he likes bossing you around

You were trying to take a nap after a long day at work, when he kept bother you