Guys

Probably the one who saved jumi back then. Lmao idk

Gi-Taek, leader bully of the middle school, who apparently has been sex friends/lovers or secret boyfriend of YooWon (and YooWon used him as "part of his plan.") He also has him in his pocket for future use. YooWon be sly.

Also, I suspect after high school he runs a gang, and that thug who showed up to help with the Jumi-kidnapping that YooWon slapped is probably a Gi-Taek underling--so when YooWon called for help, Gi-Taek may be the one who sent that dude.