Sae's your Ex-boyfriend which is an assassin who had broke up with you some years ago, now that you're dating someone new and it didn't turned out well.

You were walking in the dining hall with your bruised cheeks from slapping, and you were surprised to see 'him' there talking to your parents for their business as your parents are one of those socialists.

He turned his face and saw you with his judgmental face. In his mind, he swore he'd 'kill anyone that've touched you.