Oh it’s not that important to the story, the guy was obsessed with MC even before he became an omega.
SPOILER
The sad thing is that after he assaulted (I don’t remember the details after such a long time) MC in the past, nothing was really done to punish him because MC at the time was a beta. Most people didn’t even know he did sth. Now however, the second time that he assaults him (attempted permanent marking, keep in mind MC can not get rid of the permanent mark because of his disorder, so if he really got marked by that trash it would be the end) he gets prosecuted because of the omega protection laws. He gets harsher punishment because ML's lawyer gets involved.
Yep. Good thing ML came before he could get mark.
But you won't expect that someone's been obsessed with the omega uke. What's more that he attempted to rape him after the MC told his mother what happened they immediately move out and stay away from that man.