One Piece - I Am A Different Luffy! - Chapter 415 - 414 - Returning to Dressrosa.

He Lang died by his own hands for the sake of his imperial younger brother’s ambition, whom he loved. He was offered to be reborn in exchange for giving up his past romantic feelings. Reborn without the burden of his romantic feelings, he brings with him a manual to new worlds. He wholeheartedly followed the instructions of the manual to complete the tasks, not knowing that the originally slag gong was blackening…
He pleaded to his affectionate Emperor brother to release him, he pleaded to the paranoid prisoner next door, but until the end he remained baffled.
In the end, he discovered that the full name of the manual was – “Slag Shou Cultivating Manual”
Σ (っ ° ° °;) っ!

- Description from Novelupdates

Traveling through the fantasy world, becoming the descendant of the immortal family in the fairyland, born with a Chaos Physique, accompanied by a piece of Immortal Bone and a Primordial Seal.Starting with the Chaos Physique, he pushed forward all the way to be invincible.There are thousands of geniuses in the world, and they all have to bow their heads when they see me.

800 years ago, 3000 dimensional gates opened across the entire world. In that moment, it was as if 3000 different colored eyes opened across the world as hordes of monsters swarmed out of these gates like tears.

Some could destroy city walls with one strike; They had bodies the size of a giant and fed on humans

Some latched onto humans, absorbing their bodies’ nutrients and enslaving humans

Some infiltrated the humans’ cities, disguising themselves as normal human beings while feeding upon human blood to sustain themselves.

In a night, the Human race fell to the bottom of the food chain.

The world had turned into a paradise for monsters…

- Description from Novelupdates

In the midst of the blue and purple neon lights, under the gray, metallic sky, it is the frontier of all data, the aftermath of a scientific revolution, also the border of fiction and reality.

Steel versus body; the past and the future.

Here, the Outer World and the Inner World exist alongside each other. It seems like the wall of time is right in front of your eyes.

Darkness gradually swallows the world.

But listen, my friend, we cannot use kindness to survive the darkness. We need fire.