MMORPG: Rebirth of the Legendary Guardian - Chapter 627: Quarterfinals

Ukei Kaito fought a desperate struggle in order to fulfill his role as a summoned hero. He defeated the Demon Lord and saved the very world, only to meet an end filled but with betrayal. The companions that he’d trusted throughout his journey betrayed him and killed him by sticking a blade through his chest.

This is a fan work of “Magic Forbidden Book Catalogue”, and some settings of “Puppet Circus” are added at the same time.

A traveler from a circus enters Academy City to study and live as a puppeteer; at the same time, he secretly fights against the enemies who keep coming to seize the original magic book in his hands, and protects the safety and peace of Academy City by the way.

…The Third World War? Does the mainland dare to call it “World War” without playing?

- Description from novelbuddy

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.