You suddenly appeared one day

prolog

문별이

He is the PE teacher at Wheein's school.

정휘인

He's not a transfer student/bullied, but he gets hit by Hyejin.

안혜진

He is one of the bullies at the school that Wheein goes to.

김용선

I am a Korean teacher at the school that Wheein goes to/I like Byul-i.