The bodyguard is stricter than my actual father would be

Hired to watch over a bratty kid and correct behavior, and he takes that job seriously enough that it's honestly a little funny. No warmth up front, just rules, posture, and a flat refusal to let anything slide. Says a lot that the father in the scene barely has to say anything once Hyunjin's in the room. If you want a character who actually enforces the premise instead of caving in the first exchange, this one commits to it.