God of Death: Rise of the NPC Overlord - Chapter 54 - 55: The Return of the Revenant King

How can there be any invincibility?

How can there be any Xeon undefeated?

No one in this world can be eternally number one, anyone can be defeated.

including me.

I’ve been waiting for that one person to show up, beat me, tell me that my way is wrong.

It’s a pity that that person hasn’t come yet.

…

False martial arts: strengthen yourself, break the limits of the human body, and resist bullets with flesh and blood.

Real martial arts: use the magnetic field of life to dominate the magnetic field of the stars, use the small universe of the human body to attract the power of the big universe, travel the starry sky, and smash the planet.

- Description from novelbuddy

Arthur Ventrike, a genius second-year at the prestigious Wolkan Royal Academy, hailed to be the most talented in his generation, reaches the Swordsman stage of Knight at just 15 under Grandmaster Thorne Bladesong. But envy strikes when a fifth-year student tries to poison him. Though the plot fails, Arthur is left crippled, his dreams shattered. Just when all hope seems lost, he inherits a Great Sage’s legacy and sets out to become the greatest wizard along with the blessing of an indecent goddess and save the world from an ancient evil.

I killed the protagonist.Yeah. He was a real son of a bitch.Noah didn’t just stumble into this mess. He walked straight in—grinning, sword in hand.One day, he wakes up inside his favorite game… as a throwaway side character no one remembers. A complete nobody. But when he figures out who the so-called “main character” is?Some smug, self-righteous psycho.So yeah—he killed him. No regrets.Story over, right?Not exactly.Because this world? It’s got one more player.“WHAT THE FUCK IS GOING ON!?”Now the story’s off the rails, the world’s gone completely off-script, and Noah’s got a new goal:Steal the hero’s spot. Rewrite the plot. Find out who the hell this other player is. And maybe—just maybe—make this damn story fun for once.

For unknown reasons, he finds himself transported to a parallel world's Japan, unexpectedly taking over the body of a soon-to-be high school student who had died accidentally. Surprisingly, he did not inherit any memories. However, the first challenge he faces upon arriving here is a language barrier...Just as he struggles to communicate with his new family, a heavenly voice arrives: the black technology system has been activated, and the initial item—translation konjac—has been distributed.This is the story of someone with above-average intelligence but almost no physical strength in the Classroom of the Supreme Power.