The 31st Piece Overturns the Game Board - Chapter 417

Once, because of a pair of purple eyes he was scorned. He is a wangye known across the land, cold and bloodthirsty, looking disdainfully upon the world.

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.

In a world shadowed by death, the silent realms await, home to the undead and the Grim Reaper's sanctuary. As long as death's presence endures, the great Undead Queen will return.

It’s a story about a man who got transported into a novel and possessed a slum boy. He met a noble girl and served her as a butler for 13 Years. Now the girl has already fallen from her noble life and lives in an abandoned mansion with paralyzed legs. Why did she become like that? Of course because she is the villainess in the novel.