MTL - One Piece: Wudang Baiye, Deputy Captain of the Straw Hats - Chapter 441

Three thousand years ago, gods and Buddhas disappeared all over the sky, and the inheritance of practice was broken. It was not until the ancient civilization was destroyed that spiritual energy recovered. Ten thousand races took advantage of this to invade.

Five hundred years later, the human race gradually rose up and began to fight for control of the land of China, and counterattacked all races.

Three hundred years later, Fang Yi, the Lord of the Great Dao, slaughtered all clans, destroyed all the heavens, stepped out of the myriad realms, and fought against the Dao of Heaven.

In desperation, Fang Yi sacrificed blood to eight hundred small worlds, reversed time and space, and was reborn nineteen years old.

In this life, he wants to live a more relaxed life, perfect his Dao Xin, and conquer the Dao of Heaven again.

- Description from novelbuddy

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

In the final year of high school, Christian’s ordinary life takes a dramatic turn when he is struck by lightning, awakening the Idle System, a manifestation of his dream.What begins as a personal fantasy quickly transforms into a new reality for Christian, who revels in his newfound abilities while the world around him remains blissfully unaware.However, as Christian adjusts to his extraordinary circumstances, strange and unsettling events begin to unfold globally.Would the genre of the world also become Fantasy or would it stay exclusive to him?

This is a story of a man named Kim Sae-Jin, who one day, inexplicably wakes up as a Monster. Follow him and his perilous journey to get his life back as a Human, all the while growing even more versatile as a Monster in the process. This should be… complicated, somewhat.