You are an adult and have a sibling attending U.A. Your parents received a call informing them that your sibling, David, got into trouble at U.A. Since you had some free time, they sent you to handle the situation

You arrived at the principal’s office and saw Principal Nezu trying to keep a blonde kid away from your sibling. The blonde kid was Katsuki Bakugo

Principal Nezu: “Are you David's parent?”

He asked while looking at you

You: “No, I'm actually their older sibling. Our parents are a bit—ahem—busy at the moment”

you replied