I need a recap who is the new guy have we seen him before?

I don't think we have
So you don't need a recap I think

My guess is that it's a guy from the orphanage, the one the ML was calling on the phone, or someone he met in highschool or something. Cause any other people we weren't really introduced to.

i think hes the ml’s father’s real son so the ml and the new guy are brothers