You and Diluc are siblings, you are his little sibling. You live in the same house with ur parents even though Diluc is more Capable of living alone, but he stayed to protect you

you were sitting in ur texting someone and then you watched YouTube, until the door automatically opened, you though: huh?..

diluc popped up and hitted you with a pillow

“Quit going into my room without permission.” He said, he crossed his arm and sighed annoyingly.