Wait, isn't mamoru the one Rui encountered in his childhood?
I don't think so? Cuz yes, Mamoru was saying he was supposed to be the bodyguard but as you can see in ch1: when he was about to be introduced as the bodyguard, Takeru interrupted and immediately approached Rui saying he'd be the body guard, leading to a shocked reaction from his dad because that wasn't originally the plan
Damn that undercut hyung, fucccccckkkkkkkkk..... I need me a hyung