One Piece: Unreal Adventure - Chapter 10: Fighting Crabs?

Spend life energy to infuse martial arts, and you can perform unlimited deductions.

Shen Yi’s mortal body only has a lifespan of less than a hundred years. Fortunately, he can gain his remaining lifespan by killing demons.

In the troubled times where evil spirits are everywhere, the long sword is revealed, causing the liver and gallbladder of these creatures who have lived for thousands of years to burst!

From [Eagle Claw Technique] to [Eight Desolations Splitting Heavenly Hands], from [Demon Subduing Fist] to [Golden Body Prison Suppressing Dharma Appearance]!

Shen Yi occasionally ponders, how come this lifespan is getting longer with more use?

He put the sword into its sheath, raised his eyes to the sky, and heard that there was a Jade Palace above the clouds. It was filled with thousands of saints, each of whom had experienced endless years.

This time I came to heaven just to borrow a million years from the immortals to prove my path to immortality.

- Description from novelbuddy

In the 900th millennium of humanity's journey towards the Star Sea, the unstoppable Expeditionary Army dominates the universe, and the fiery Age of Great Expansion nears its conclusion.Ancient cultivators seize mythology in pursuit of becoming sacred Buddhas; the new generation of prodigies shatter shackles, yearning to surpass limits!Yet, in a secluded corner of the vast cosmos, Qin Shi chooses to grind through countless achievements, unlocking one monument after another.Until reaching the pinnacle of evolution, the ultimate summit!

“I'm one game away from reaching the master rank! I'll do it tomorrow, though. A true gamer knows when to refresh his mind and increase his victory chances!”Adam smiled in anticipation as he went to sleep on this special day.However, he could never have imagined the surreal awakening that awaited him.“What's wrong with my voice?!”“Claws? A tail and horns, too?”[Welcome to the demon realm. You have been selected to reincarnate as a Lord. Conquer this realm of fire and ashes, become its uncontested ruler... or die trying.]Reincarnated as an imp in the cruel demon realm, at the borders of the mythological demon Baal's territory, his life seemed doomed from the start.However, determination sparkled in his eyes as against all odds, he defiantly proclaimed.“No matter who decided to make me start as an imp, watch as I turn into a veritable devil. Even Baal won't hold a candle against me in the future!”Equipped with his unique talent, he started his lord's journey, ready to evolve and prove to those strange realms that demons were more than violent and deceptive creatures... at least he would try.

I returned after 10 years.