One Piece: Supreme Check-In System - Chapter 65: Oaths of Steel, Bonds of Blood

Anger. Pain. Desolation.

The dawn era after the end of the half century has gradually rebuilt the order, abandoned civilization, and is full of undivided violence and desire.
The noble and powerful pioneers are in charge of the city, and the evil and mad plagues are in the wilderness.
Pure human beings who cannot mutate are the weakest, dominated by the rulers of the pioneers, and are not as good as animals in the wilderness.
A purely humanized young man with a worldly experience has quietly entered the WTO, holding a three-foot long knife and a long-distance desire to boil in the world of purgatory. From the nameless name to the sorrow of the Supreme Court, the name of the black ride is resounding!

- Description from Uukanshu (translated)

The World of Ephesus. A vast world plagued by Breaches containing countless Beasts of Corruption. A World on the brink of ruin as the Four Human Lineages defend the last bastions of Humanity! With the power of Gem Masters standing against the Beasts of Corruption, the flames of Humanity seek to burn ever brighter. In such a world, in the Mortal Branch of the Asmodeus Bloodline, Alexander awakens a Gem Socket that others consider defective. A Variant Gem Socket. Looked down upon by those who do not understand it, this supposed defect may just be the solution that the burning embers of humanity were waiting for. Follow Alexander as he entirely warps the perception of what a Gem Master is- as he embarks on a journey to become...The Empyreal Gem Master!

Jin Yeong was just another office worker—forgettable, unremarkable, and stuck in a life that never went anywhere. He wasn’t strong. He wasn’t talented. In a world of ambition, he was just… there.Then, the sky cracked open.A voice echoed across the world, mocking humanity’s weakness. A system was given. A chance to survive.People awakened powerful abilities—fire, lightning, super strength. Jin got this:[Limitless Weapon Mastery]“Any weapon you wield is used at its maximum potential.”No fire. No magic. No enhancements. Just a simple skill?But soon he and the world will learn a simple truth:It’s not about what you wield. It’s about how you wield it.