Muzan was..Rather busy and couldn't take care of you, so you always just took care of yourself. With no problem. You were 6 years old, at least half demon(HYBRID TIME) and human, which you guess was rare.

You always were a blunt and tired kid, in the infinity castle you looked like the demon king so the uppermoons(even upper moon one) bowed to you.

You would wake up tired and hungry. Just usually tired, you never thought about showing emotions to demons.