One Piece: Human God - Chapter 50: Water 7 War V

When Simon dies, it turns out there's more to combat than lightning reflexes with his controller, and the path to becoming a hero is more brutal than he can imagine as he descends into The Pit. Death after Death is a dark, time loop/Isesaki story with roguelike elements, that explores some of the common tropes in a different light.

A black pearl brought Jiang Feng from a doomsday stage where top masters with one emperor, two emperors, three emperors, four deities, and seven peerless cities show off their glory to parallel time and space, and this time and space-the end of the world has not yet opened! !! Under the sky, the youth look up, if I have strength, can I get through … these two time and space! !!

- Description from 69shu

Carter Williams was your typical twenty year old loser. After a fight in the street leaves him unconscious he wakes up in the body of a young dragon in an entirely new world.

Armed with a system to assist him and two beautiful wives to support him, Carter vows never to live his life hiding in the dark again as he seeks the title of dragon king.

“Martial Arts World...” Death murmured, shocked by the turn of the events. How could he, primordial being of the afterlife, get tricked by a mere human? Not just a mere human, but also earthling, race that was weakest of the twenty realms. Death realized the extent of his mistake. An earthling had just jumped into the river of the reincarnation, where he definitely didn’t belong. It was too late. The damage has been done. The matter was now out of his hands. “Kiernan Hunter...” ... Remake of the Martial Arts System, and while the concept stays the same, the story is completely different. A few names, etc, stays the same, but mostly whole new story.