the thing is... I think he knew mc wasn't a monster in the middle of the fight but kept going cuz his pride was hurt so he wanted to get rid of mc even if he knew he was human. #－.－)
I don't think it's just about pride, he said there's no way someone younger could be so strong so it must be a monster disguised as a student. Seems logical since mc has monstrous aura and power.
Based on what you said there's pride in there too. Him, can't believe that there's someone YOUNGER than him to be STRONGER than him sounds prideful to me. Tho, it is logical to be cautious but you can't deny there's at least a little pride in that time when he did that conclusion.
Besides when I read that I didn't feel that he's logical tbh. So I felt the same way with Mafuyu.
That dude that attacked mc thinking he was the monster without even confirming he was ,like what that’s just asking to die. I get annoyed by people like him. (╯°Д °)╯╧╧