I think the new guy is the MC from future he came to the past to stop blue haired guy's death. And the that senior (blue haired guy's brother) must have some inferiority complex with his younger brother, probably some family drama. He know that his younger brother likes MC , he also know MC likes him (senior). He don't actually like MC, he just wants to hurt his brother. And the MC is an idiot who can't sense that senior's malicious intents. Maybe the senior may genuinely like MC and he is threatening his younger brother or something so he can get MC. Anyway I hope the blue haired guy will get his happy ending, probably MC gonna end up with him.
I think the new guy is the MC from future he came to the past to stop blue haired guy's death. And the that senior (blue haired guy's brother) must have some inferiority complex with his younger brother, probably some family drama. He know that his younger brother likes MC , he also know MC likes him (senior). He don't actually like MC, he just wants to hurt his brother. And the MC is an idiot who can't sense that senior's malicious intents.
Maybe the senior may genuinely like MC and he is threatening his younger brother or something so he can get MC. Anyway I hope the blue haired guy will get his happy ending, probably MC gonna end up with him.