Maou-sama no Machizukuri! ~Saikyou no Danjon wa Kindai Toshi~ - Volume 6 Chapter 3

In a tyrannical world, what is evil? What is benevolence? All living creatures are brutal. Passing through the heaven road to find one’s purpose in life. Struggles to be stronger is not an easy path. The whole journey thistles and thorns, one blade chops open a path, I alone will be supreme!

- Description from Novelupdates

In the age of the Great Liang Dynasty, the lives of the people were made convenient with steam-powered machines that run on a fuel named Violetstream Gold. Chang Geng, who lived in a small countryside village, shared a distant relationship with his mother while his stepfather was away most of the year round, and the only people he was close to were two little kids, the village teacher, and his yi fu – adoptive father. But his life was flipped upside down one day following the barbaric Man tribes’ invasion, and it turned out that his entire identity had been an illusion – not only was Chang Geng himself not the country boy he thought he was, but also his mother, his teacher, and even his beloved yi fu…

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.