I still don't know since he hasn't appeared yet I checked the raws incase if he appeared in the later chapters but no he didn't and he was like a silhouette and over that we can't even see his face since he's facing backwards so idk if he's really another love rival or something else but we will see in the future
I think he will try to get revenge at first but he will change his mind, Iltak is slowly changing and it is clear that he is feeling guilty for having bullied that guy, so here is how I think it will go: He changes school and meets Iltak again, he will try to get revenge but Iltak feeling guilty apologizes, and also because the guy has become "cool" from Iltak's point of view, so the two become friends again, the other two rivals become jealous, the bullied guy in my opinion will be the opposite of the other two, clearly showing affection towards Iltak, even flirting, but Iltak is stupid and will not notice it

GUYS I JUST SAW THE FULL COVER PHOTO OF THIS MANHWA AND APPARENTLY THERE'S ANOTHER BIG GUY WHO HASN'T BEEN INTRODUCED YET I COULDN'T SAW HIS FACE SINCE HE WAS FACING BACKWARDS BUT OMG I THINK HE MIGHT BE ANOTHER LOVE RIVAL WHO KNOWS?