One Piece: The Overlord of the Old Era at Fifteen

I transmigrate to the old era of the pirate world, never touch a single Devil Fruit, and am born with all Three Types of Haki at their peak. I craft my own Seastone sniper rifle with my own hands. I venture across the open sea alone, defeat entire Marines fleets single-handedly, and face CP9 agents head-on. Even when I chance upon the Roger Pirates, I remain a lone pirate. Relying neither on bloodline nor on the protection of companions, I forge a legend all my own as a long-range powerhouse, armed with a single rifle.

No Devil Fruit, Seastone firearms, Three Types of Haki, lone pirate, old-era fan fiction, long-range sniping