My Demon Hunting System - Chapter 14: The Realm for Warriors

The Immortal Path led to Longevity and Sovereign was heading in ease. When the Longevity was no longer in ease, all living beings were just prisoners. Conspiracy, internal strife, and the invasion of the others, all of it emerged together. 

In such a world, there was such a young man. He made his way upstream, stepping on blood, defying the emperor, destroying the various kings, and slaughtering his way through the hundred clans to form an Immortal Path towards the throne of Sovereign! The Immortal Path was endless, while the Sovereign was limited. He used his blood to forge his immortal legend.

- Description from Novelupdates

One day, a silver-haired goddess appeared before him.“Heaven-Defying Star. The one who goes against fate. The sole savior of a world doomed to end—”What the hell is this woman even talking about?“You must be the Regressor.”“… What?”No, I’m not.

their example, leading to continuous warfare! However, the aboriginal people of this otherworld who have been blinded by the aesthetics of violence! Rightnow! And in the future! Let me teach you what kind of mecha represents the romance of a man! Let me show you what kind of propulsion is the iron torrent! Let me instruct you what kind of weapon is the deterrence for peace (implied by “nuclear” here)! Let me! Teach you! What exactly is the air-to-ground cluster offensive and the all-round air, sea, and land strike!! Gentlemen! I, indeed, love war! But what I love even more is to stop war with war and bring about a prosperous future where the whole world is unified for thousands of generations! Unite all nations and subdue all races! When the whole world is united as one, it will last forever...

This is the story of a young slave gladiator in an underground arena. He doesn’t know about his past or how he got to where he is, only that his name is Aegir, and that he is strong.