MTL - Yu-Gi-Oh!: Underworld Boss, Cancerous Creator God - Chapter 13

Zhu Kang, a trafficked soul, was captured by an evil organization and was stripped of his real memories. Unaware of the dangers he worked for this evil corporation as a system.One day, all of a sudden, fifteen men dressed in black started a shoot-out killing all the other systems.In desperation, Kang threw himself into a transmigration device that tossed his soul into a random world.“System 202 has escaped.... a-again.....” one of the black-clothed men said. Trembling, he glanced at their team leader.Kai Alden gritted his teeth. “You let him slip away so easily! Send me into that world. I will capture my dear System and bring him back here,”

Riven was nothing but a powerless runt until necromancers razed his village and butchered his sister before his eyes. As his blood soaked the dirt, his Sigil ignited, granting him a gift. He can die and reform, a cycle that resets with every rank he climbs.But fate wasn’t done screwing him.In the catacombs beneath the ruins, he found the Death Ledger—a death contract that bound him against his will to hunt those who’ve cheated death across dimensions. Historical legendary heroes and villains.From the noble King Arthur to the conqueror Genghis Khan and the fabled king of Uruk, Gilgamesh, together with Ivan the Terrible and Vlad the Impaler.Every mission is a gamble. Fail once, and the Ledger brands him a death-cheater, turning him into prey for the same immortal fugitives he hunts. And the reward? He gets to keep them as his undead summons.His enemies will not stop coming. They want the Ledger, the Sigil, his power. To survive, he will wield death itself, growing stronger with every soul he claims, because in a world this savage, only the relentless rise.[-Congratulations, you have successfully killed Alexander the Great and claimed him as your summon...you can start on the path of evolution-] The words, scrawled in blood, burned across the page of the Death Ledger.

A master assassin transmigrates into an interstellar era.

Other players were responsible for competing in the e-sports arena, while he was responsible for stringing up and beating up the other players.

His sword was hidden during the peak of day, and he was a gentleman who arrived in a flash of light;
As a vanguard of the eternal night, he was the variable between life and death in the world.

“As you know, the Star League’s difficulty levels are arranged in this way:
Paradise < Simple < Normal < Difficult < Nightmare < Hell < [Tyron Odin]”

- Description from Novelupdates