Reborn: Super God of War - Chapter 712： Real 5-Headed Dragon

An ordinary student accidentally traveled into an other universe and became the king of a small kingdom. He had gotten a “Cheating Code” of life and was able to complete something extraordinary. This is the story about a king that was able to conquer continents and leave behind him an ultimate legend that will be recited between every generation to come.

- Description from novelupdates

Sano Yuji, a black company employee, is summoned to another world while finishing his work at home. His profession in the other world, a Monster Tamer, is considered a job that makes it difficult to become an adventurer. However, thanks to some slimes he met, which read several magical books, he gained magical powers and the second profession, Sage. Yuji acquired overwhelming power, but is he conscious of his strength? Blindly becoming unparalleled and strongest in the world!

Thirty thousand years ago, the Heaven Fighting Race who called themselves “Gods” invaded the Spirit Realm. Hundreds of races rose up in resistance, but ultimately suffered a crushing defeat. The Human Race was the first to concede, and the rest of the Hundred Races soon followed in succession.