The Demon King and the Savior Are Obviously Made for Each Other

[Two male leads + Western fantasy + younger top + equally powerful leads + reborn]

Finor Christian was the youngest genius in the history of the Esos Continent.

He died saving the world.

Then he was reborn, 500 years later, in the body of an obscure young man.

Finor: (gasps)

The Son of Light who once saved the world has possessed someone else's body to be reborn. Is this a distortion of human nature, or a collapse of morality? (Finor: I didn't! I swear!)

Even more terrifying, now that he has magic, he has to attend a magic academy.

A commoner attending a magic school full of nobles...

As someone who was never good at socializing, is he going to become the most hated person at the academy...?

The setting is fictional, so there are lots of original details.

It's not purely a school-life story; school life only takes up a small part.

The bottom isn't exactly loved by everyone, but plenty of people do like him.

There are other male and female coworkers, but they don't get much page time.

The top has tentacles and is a crybaby with gravity-based powers.

The bottom is laid-back, unconcerned with worldly affairs, and has little ambition.

I can't think of any potential triggers for now. Let me know if there are any, and I'll add them.