After transmigrating as Monkey D. Karon, brother of Garp, he receives the Nine Yang Divine Skill, top-tier Three Types of Haki, and an Iron Balloon physique from the System. He fought alongside Garp and Roger at God Valley, then went into hiding in the East Blue after growing disgusted with the World Government’s corruption. In secret, he trains Luffy and the other two members of the trio, laying a foundation for them with divine techniques and Haki while instilling in them the will to be free.
During the Paramount War, he transforms into the “Diamond Dragon” and saves Ace, openly rebelling against the World Government. Afterward, he joins forces with the Revolutionary Army and unites various factions, including Fish-Man Island, to uncover the truth behind the century-long mystery. In the final battle at Mary Geoise, while Luffy faces Imu, Karon leads the allied forces in crushing the divine authority with his Nine Yang Tyrant Fist, ushering in a new era of freedom.
