One Piece: The One-Punch Admiral, I Punched Akainu to Tears

(The rating just came out. It'll rise later.) Lin En transmigrates into Pirate King with Saitama's template, but has to stick to Saitama's training routine for two and a half years to activate the System.

At last, one day after awakening the template, the sea trembles.

Whitebeard: “I admit that he's the world's strongest man.”

Red-Hair: “I'm afraid even my influence won't be enough this time.”

Garp: “What Iron Fist? In front of Lin En, I don't deserve to be called Iron Fist.”

…