Good News: He transmigrated into an anime world and awakened an omnipotent ability.

Bad News: He's ill.

...

Takanashi Rikka: "Oh most trusted ally of the Evil King's True Eye! Let us witness the world's ultimate truth together!"

Murasakibara Saeko: "Please accept me as your disciple and teach me supreme swordsmanship!"

Kobato: "Kukuku, my other half! Come awaken my sealed power!"

Eri: "Idiot! Stop acting crazy here!"

Shinjou Masuzu: "Your first kiss partner isn't Eri - it's me, Shinjou Masuzu!"

Dekomori Sanae: "I beg you! Grant me power! I'll do anything, death!"

Gu Changtian accidentally travels to the world of One Piece and is bound to the One-Punch Man Summoning System. In the One Piece world, he establishes the First Legion and continuously accumulates shock points.

Such a terrifying demon has crossed over into the world of One Piece. What will become of the One Piece world...?

"The Warring States period was terrifying; the First Legion members were all like monsters..."

Whitebeard: "Giants are the strongest men in the world..."

Redhead: "Oh no, my pride isn't working anymore..."

Garp: "Even my iron fist can't beat the First Legion..."

Kizaru: "No matter how much money you offer me, I won't fight the First Army..."