Except, the Heroine and the MC are just "fake lovers", and the MC acts as a deterrent for the other male students since the Heroine is considered an extreme beauty.

The character, that the MC takes over, only serves as a plot device that powers up the Heroine in the story. Other than that, he's supposed to get killed off to contribute to the Heroine's character growth.

The MC breaks up with the Heroine so she can get closer to the other Male Leads. Since if the MC stays as the Heroine's boyfriend, then the Male Leads won't be able to foster a close relationship with the Heroine. (They'll be deterred at the fact that she has a boyfriend)

Which is important so that the Heroine gains the Male Leads as allies, just like in the original plot.

But the Heroine still has lingering feelings, since both her and the MC have spent a lot of time together as a fake couple.

But she isn't aware of her own feelings yet, and so she just harbors a small jealousy towards the Villainess who has teamed up with the MC.

As a test of character, a professor (forgot their name) shows their bloodlust towards the students.

The MC resists the intimidation, and casually looks over the frightened students who are struggling against the professor's bloodlust.

The professor takes note of this, and becomes interested in the MC's capabilities as a commander. (Since he has a calm demeanor, and possesses a tactical mind. Despite being weak.)

The MC's strategies PERFECTLY go as planned. To the point where the Villainess (who teamed up with the MC) questions if the MC has precognitive abilities.

Although, the Villainess and her lackey get all the spotlight. Since the MC lacks the combative abilities to contribute to the team. (But the MC comes up with the plans)