Youkoso Jitsuryoku Shijou Shugi no Kyoushitsu e - Volume 13, Chapter 5: An invitation Part 1

The world is in an age of change between the old and the new society, and the collision of politics, economy, thought and culture is becoming more and more violent.

Moster Verak, a photographer from the slums of Zward City, was reborn two months ago, starting from impersonating the son of a consortium again, stirring everything and subverting the world in the turmoil of rapid industrial development and wild expansion of ambition.

[Overhead world, please do not compare reality]

- 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.

Hundreds of years ago, Human, Celestial Clan and Demon Clan lived together on the Origin Continent. However, a great war broke out between the three races. Shan He, the leader of Human, had discovered a catalogue of methods to forge Divine Weapons. With this catalogue, Shan He led Human to defeat the other two clans and expelled them from the Origin Continent.

The peace did not last long. After the passing of Shan He, the once Glory Empire collapsed. Various forces of Human fell into a long period of wild war for the Divine Weapon Catalogue, but the catalogue was lost during the war.

The Demon Clan took advantage of the internal strife of Human. Under the lead of their new lord, Fen Tian, the Demon army invaded the Origin Continent violently.

Human soon lost a large portion of their territory. At that moment, a mysterious hero suddenly appeared on the battlefield. With a legendary Divine Weapon in hand, he severely injured Fen Tian and forced him to retreat. The united Human army chased the Demon army across the strait and to the Two Realm Plain on the Tranquil Continent.

Once again, the various forces of Human started wildly searching for the Divine Weapon Catalogue…

- Description from Novelupdates

「Shimizu-san, you dyed your hair black.」「Ah, yes.」「Why did you dye it all of a sudden?」「Because…yesterday…」Shimizu-san, who sat next to me and had dyed her hair from blonde to black gradually lowered her voice, slightly blushed, and laid her face down on the desk.