In This Life, The Greatest Star In The Universe - Chapter 17:

Aomori, who has a monster-fighting system, came to the world of One-Punch Man and gained the ability to enter various instances.

Therefore, “Founder of the Hero Association”, “NO. “And other titles fell on him one after another.

Comprehensive flow, the main world One Punch Man.

Completed dungeons so far: Pokémon – Demon Slayer – Sword – Pokémon – Digimon – Spell Return – Yokai Comprehensive World (Girls that Noragami Inuyasha can see, etc.) – Pokémon – One Piece-re0-Dragon Ball wait.

- Description from novelbuddy

The ancient continent of Wu is a place where cultivation is law and the strong reign supreme. Thousands fall to their knees when the strong appear, and rivers of blood flow when they’re angered.

A peak expert known as Xie Di fell and was reborn in a young man beaten into idiocy. He lost all of his memories and his cultivation was crippled, causing him to be despised by all. To rid his shame and fight against the destiny of being toyed by others, the young man cultivated with all his strength, killing experts, and splattering the whole country with blood. All until the day he becomes a martial god who shatters the firmament and scorns mortals.

In the waves of steam and machinery, who could achieve extraordinary? In the fogs of history and darkness, who was whispering? I woke up from the realm of mysteries and opened my eyes to the world.

Ryuk’s life in the forsaken Grade E city was bleak, but it truly shattered when a Knull raid took his last family and left him for dead. On the brink of despair: [System Activation Complete.] [Congratulations, Host has awakened the Draconic Pets Evolution System!] [Welcome host, to the path of domination.] Thrust into Endearth, a shattered mirror of Earth teeming with mythical creatures—vampires, werewolves, cosmic gods—and the unstoppable Knulls, Ryuk sets out on a journey of relentless growth, vengeance, and discovery. But power comes with a price, and the dual nature of his gift could either save humanity or destroy everything. This is a story of evolution, redemption, and defiance. Join Ryuk as he rises from nothing, building unshakable bonds with allies and carving his path in a world where strength is the only currency.