Luffy got the scar on his chest during the war at Marineford, in One Piece anime episode 487 titled “Akainu’s Tenacity! The Fist of the Magma Attacks Luffy”.
|Episode Number||Episode 487|
|Episode Name||Akainu’s Tenacity! The Fist of the Magma Attacks Luffy|
|Manga Chapter||Chapter 578|
|Chapter Name||A Present to the New World|
Blackbeard, one of the major antagonists of the series, vowed to destroy every inch of Marineford and sink it in the sea as the discouraged marines gazed on in fear and anxiety. Sengoku, Fleet Admiral at the time, offered a stirring speech to the marines before suddenly unleashing a shock wave from his palm to smash Blackbeard and his pirate crew. Koby is perplexed by the Justice of executing pirates, after the Marines had unquestionably won the war when they attacked the Whitebeard pirates, who were still alive and retreating.
Meanwhile, Akainu persisted in his unrelenting pursuit of Luffy and Jinbe. He punched Jinbei from behind with his magma punch, piercing Jinbei’s body and gravely wounding both Jinbei and Luffy. This later gave Luffy a cross-shaped scar on his chest. Crocodile (a former warlord), along with the other Whitebeard Commanders and pirates, got in the way before both of them were killed.
Buggy caught the thrown Jinbe and Luffy and was unclear about where to go or what to do with them, when Trafalgar Law, captain of the Heart Pirates appeared on the scene and instructed Buggy to bring Luffy to him, because he was a doctor and he could save him. Law unexpectedly showed up and stated that while Luffy will one day become his enemy, since that would be a worthwhile relationship, he will still provide for his medical needs and save his life.
A. Luffy got the cross-shaped scar on his chest from Akainu, a Navy Admiral at the time, in the war at Marineford.
A. Luffy got the cross-shaped scar on his chest in chapter 578, titled “A Present to the New World.”