Supreme Tamer - Chapter 397 - 273: The Underground World, God’s Innards

Nine heavens and nine earths, there are many souls.

The strong stand in the nine heavens, like shining stars, while the weak creep on the ground like tiny ants.

The young boy Bai Ye accidentally unlocked the mysterious heavenly soul, cultivated supreme soul skills, guarded the soul and sword, rushed into the nine heavens and swept the stars, and the legend began…

- Description from MTL

Reborn as Red Army Misha!

- Description from novelbuddy

Mana finally arrived in our world after being delayed for unknown reasons, causing the evolution of everything that had life.

Humans, plants, and monsters all evolved, ushering the planet into a new era in which old laws no longer applied and the only law in the world was the rule of the jungle, where the strong preyed on the weak.

It was a question of whether we, the 'rulers' of the land, would be able to maintain our position and adapt to whatever came after our planet's awakening, and if we did, was that the end?

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.