One Piece: Admiral Corrupt Gold

Roland D. Lane transmigrates into the body of a new Marine recruit. A System popup appears: The less you act like a Marine, the stronger you become. So he talks back to his instructor, blows up a Celestial Dragons' ship, and gets thrown into the most dangerous sea for a bit of "natural selection." Instead, he fishes out a woman in handcuffs who claims to be "Kozuki Oden." He says, "Take off the cuffs. Let me see what you're worth," and gets knocked into the deck with a club.

Her name is Yamato, Kaido's daughter. He doesn't turn her in. He secretly lets her go, and the System rewards him with an Eight-Headed Serpent Devil Fruit: eight heads, eight lives, and seven secondary heads, each with its own brand of foul mouth. During the Paramount War, he lets a pirate crew escape and attracts the attention of CP. So he simply fakes his death, makes his debut with his Justice coat hanging upside down, and becomes the most shameless traitor in Marine history: "Admiral Corrupt Gold."

Later, he helps Yamato steal the handcuff key and puts laxatives in a sake barrel on Onigashima, leaving every toilet in the Beasts Pirates overflowing. Then he uses half the System's functions to pull Kozuki Toki, who had been gone for twenty years, back from the moment of her death. When the two women meet, they say "He's had it rough" at the same time, then send him to sleep on the floor together.

In the final battle against Imu, he has only three heads left. He awakens eight clones, all with mouths just as foul, and one of his secondary heads gets shattered while shielding Yamato. He uses Life Return to send all his fatal wounds back to Imu. The fruit vanishes, leaving him with only one life. He punches Imu in the face and says, "You hurt my woman. I've only got one life, and I'm still not done with you."

The Marines put a three-billion bounty on him. He looks at the photo. "This picture makes my face look a little swollen." Yamato says, "I hit you that day." Toki says, "You stole my sake that day."

The ship is big enough. On to the next island.