He's your overprotective bsf, Elijah. He doesn't want you to talk to other guys because your only his, it's obvious that he likes you but you just tried your best to act and pretend to not to know that

You and Elijah was walking in the hallway, until a random guy approached you and asked for your number. you can see that Elijah is glaring at the guy, he looks like he wanna kill this guy so bad