I think he's the one got attacked at prologue. He probably get infected and his body build antibodi that makes him half zombie half human. I see these kind of theme in other manga.
Thought the same, but student he saw getting attack at school had 3 beauty marks on the right side of the face.
I also believe he is someone that was attack and build some antibody like you mention. But what makes me doubt a little is that the other dude had to tell him the ML needed to eat something or he will die. That should be common knowledge.
Unless is cuz, he was so into it that he forgot about that fact. ╮(￣▽￣)╭
okay okay thank you
fhis so confusing for me. Like is that the dude from the higschool and he a zombie or something..? SO CONFUSING