Naruto System in One Piece - Chapter 129

Apocalypse befell, and roommates performed a skyward ritual.As the fog descended, the Book of Blood Spirit appeared in the hands of all survivors, and only those with a Contract monster could survive.Su Han directed his gaze to the neighbor who had already mutated and twisted, silently pulling out a gleaming fruit knife...Grotesque meat corpses, giant spiders with gaping mouths, eyeballs enveloping the city, one-eyed sharp-toothed hand monsters...Civilization fell, cities shattered, and all humans became meat for the monsters. There was only one way to survive:Use monsters to fight monsters.

Gawain is dead and was transmigrated, but there was a slight problem during the process.
After floating for more than a hundred thousand years on a different continent, he felt that he might need a body to become a complete transmigrator, but he did not expect that…

- Description from Novelupdates

A child was born unable to cultivate Inner Strength. In order to gain his father's attention and regard, he resolutely chose the painful and difficult path of cultivating Outer Strength. As spring gave way to autumn, time flew by, and the child grew up... he became a young man. What truly changed his destiny was a mysterious Crystal Stone formed from a meteor—the Meteor Tear. This Meteor Tear, unbeknownst to the young man, merged into his body, and like a caterpillar transforming into a butterfly, the young man metamorphosed... And with that transformation, everything changed. And his father finally came to realize the astonishing strength of the son he had never truly invested his Heart Power in...

[Volume 1: Dante Blackthorn]When Anastasia and her sister Marianne are captured and shipped across the seas by pirates, they become commodities to be sold in a distant land. Marianne is taken as a courtesan, while Anastasia barely escapes a terrible fate by pretending to be mute. She is forced into the lowest ring of servants at the royal palace, where she endures a life of servitude and creates beautiful artwork to mask her pain.Despite years passing, Anastasia has never forgotten her sister's promise to return to their family together. However, with her movement restricted and the guards vigilant, escape seems impossible.When Anastasia comes into contact with the Forsaken Prince, her life spirals out of control and she triggers a Crux of incredible proportions. Now battling her own inner demons while navigating the treacherous politics of the royal court, Anastasia must confront the truth about her sister's fate and make a choice that could alter the course of an entire kingdom.[Volume 2: Emily Blackthorn]Princess Emily's life takes a turbulent turn when she is rejected, leaving her heartbroken and her soul at the brink of corruption. In a desperate bid to save herself, she journeys to the West.Enter the Storm Prince, a charismatic archdemon with striking blue eyes, with a saint-like smile. Emily had hoped she'd seen the last of him, but fate has other plans. As if her soul dying isn’t enough, someone wants to steal it!Caught between the suitors and the haunting nightmares that have plagued her since childhood, Emily begins to see Raylen in a new light. The blue-eyed demon may not be the monster she once thought.