The Husky and His White Cat Shizun - Chapter 308: [The sorrow of death]

"I hope my wife liked the arrangements... for the wedding night."

Shu finished the final chapter of a hated apocalypse novel, only to wake up inside it hours later. In Zoxhia, dungeons open without warning, monsters flood the streets, and even the strongest heroes die miserable deaths.The only reason Shu has not joined them yet is a cheat no one else has ever seen: a Domain that can grow into an absolute safe zone. Armed with incomplete knowledge of the story, a dangerous system, and a world already heading for ruin, Shu has to survive, grow stronger, and change an ending where the demons win and everyone dies.discord: https://discord.gg/WkyX6NuZZA

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.