MTL - I Can Rewind - Chapter 14 Time limit ten minutes (five)

Seven years ago, after their breakup, he disappeared without a trace.

The worst student of Westroad Academy. The disgrace of the Blake House. A new soul enters the body of Frey Blake, who couldn’t overcome his miserable life and chose death instead. “What’s with this body? I’ll have to work on tuning it from scratch.” The Great Mage Lucas Traumen, with the body of Frey Blake, gains a chance at revenge!

Offered as a bride to Hades at the age of eighteen.

Pestered by evil spirits in the day, and taken advantage of by a perverted demon at night.

Pervert: “Dear, a night with you is worth more than gold.”

I leaned away as I clenched my teeth angrily: “Worth my foot!”

- Description from Novelupdates

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.