Naruto System in One Piece - Chapter 37

Benedict was transported to a world of cultivation and awakened the Invincible Domain system. Within this domain, he was invincible!

A fighting genius.

Cairn is a prince who is already tired of ruling. Faced with an imminent coronation and an overbearing father, he wants nothing more than to drown his responsibilities in cheap liquor and poor decisions. With the help of his sister, he hatches a plan to escape the clutches of the throne once and for all. It all goes terribly wrong, and Cairn finds his priorities shifting in the face of unimaginable tragedy. The change of heart comes too late, however, and Cairn dies. He reawakens to find himself transported ten years in the past. He immediately begins to plan for the future, only to discover his killer has somehow followed him. To succeed, Cairn must unite the kingdom and discover the motivation of his killer, using as many tries as it takes. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++I exhausted pretty much every time loop story ever written and decided to write my own. You'll see a few similarities here between this story and some existing stories, at least initially. There's a lot of inspiration drawn from both MoL and Re:Zero, though in terms of pathos and darkness, this story leans more towards the latter. Be warned, it is something of a slow burn. The main character will grow and become powerful, but a theme of this story is that power comes slowly and often at great cost.

Worlds overlapped, and Alien Species descended.Strange entities emerged one after another, as the shadow of evil spread wildly.The calm of life was shattered, and Zhang Xiaoman, inside a fish's stomach, accidentally consumed a system named “World-saving Plan”.From then on, he became the only person among all humans with Extraordinary Power.…Inventing an ancient oath, he established a unique methodology, Cultivated Dark Energy, founded an organization, took Control of the Transcendent, and resisted invasions.Well, this is actually the story of how a Big Con Man bluffed his way into saving the entire world.PS: Contains elements of the behind-the-scenes, Cthulhu mythos.