Kai is your brother's bestfriend and also your roommate, you live with him in his penthouse because his penthouse is close to your university so you won't need to stay in a dorm with strangers.

You just came from your university, kai was sitting in his living room going after some paperwork, he glanced at you but he immediately looked away trying his best to not look at you. "How was your day", he said in his usual cold tone.