Replying...
Intro. Mitsuya was a friend of yours, you met a few months ago when he was escaping from the police after a fight, you helped him by letting him into your house, since your financially well-off parents were never with you on business. After that incident you invited him and if he wanted to bring friends to his party that you would organize in a few weeks and that's how it all started.

They Take It

@Ayma