One Piece: Slow-Slow and Door-Door Make Me King of the World

[Set about twenty years before Luffy sets sail + Two Devil Fruits (Slow-Slow Fruit and Door-Door Fruit) + No heroine for now + Three Types of Haki + Sword God + Establishing a faction + A System appears at the beginning (only in the first three chapters)]

[Tentative companions: Gild Tesoro + Fish-Man Hero Fisher Tiger + Tyrant Kuma…]

World News Reporter: How do the powerful figures of the seas view His Majesty Ron, the King of the World?

Shanks: Ron may not be one of the Four Emperors, but he’s even more terrifying than they are. He’s the true King of the World.

Whitebeard: Ron is so strong. I wish I could be his son.

Charlotte Linlin: I’d love to marry every woman in my family to Ron. If he doesn’t want any of them, I could always go myself.

Kaido of the Beasts: Boss Ron, please stop hitting me! I give up. You’re the Strongest Creature on land, sea, and air.

Blackbeard: Where’s my Dark-Dark Fruit? It turns out Ron has it. Well, that’s that, then.

Kong: I only want to prove my loyalty to His Majesty Ron.

Garp: How come this kid’s fists are even harder than mine?

Akainu: Why can my justice never reach him!

Kizaru: Ron, he, he, he’s my natural enemy!

Aokiji: Ron’s arrival has shown me a new direction for justice.

Dragon: Comrades, the revolution is over! This is the age of Ron!

Imu: This guy is even more terrifying than Joy Boy!

Luffy: I’m going to become the Pirate King! What? Ron has already brought the age of pirates to an end?

Ron: I just wanted to be the world’s overlord. How did I end up as the final boss?