The war at Marineford, between the Whitebeard Pirates and their allies against the entire Marine forces, including Seven Warlords of the Sea, started in episode 461 of the One Piece anime, titled ‘The Beginning of the War! Ace and Whitebeard’s Past!.’
The Whitebeard Pirates waged war against the Marine to rescue their Second Division Commander Portgas D. Ace from execution. Marshall D. Teach, famously known as Blackbeard, defeated Ace and handed him over to the navy which eventually led to the Summit War of Marineford.
|Episode Number||Episode 461|
|Episode Name||The Beginning of the War! Ace and Whitebeard’s Past!|
|Manga Chapter||Chapter 552|
|Chapter Name||Ace and Whitebeard|
Along with the Moby Dick, three more ships have entered the Marine Headquarters Bay in Marineford. The infamous Moby Dick, the Whitebeard Pirate Ship, emerges from underneath the sea using the coating to sail underwater. As he appears, Edward ‘Whitebeard' Newgate, the captain of the Whitebeard Pirates, states that it would be best for everyone if his son, Fire Fist Ace, is alright.
Ivankov is ignorant that Ace is not biologically related to Luffy. She suggests that Luffy meet his father (Monkey D. Dragon) today since he will show up there to save Ace and never allow his son to be killed. Luffy responds that, while his father is Dragon, Ace's father is actually Gol D. Roger. Ivankov is shocked by this new development.
Ace then reminisces on how he left the Goa Kingdom to become a pirate, leaving Luffy behind, his time as the Spade Pirates' captain, and his meeting with Shanks on a winter island to thank him for saving his little brother's life. He remembers his encounter with Jinbe and Whitebeard. Although he fought Whitebeard and lost, Whitebeard grew fond of him and took him to the Moby Dick, where he got some medical treatment, allowing his wounds to heal. Even though he saved him, Ace would often attack Whitebeard but got nowhere. Through all this, he always wondered why everyone referred to Whitebeard as their father, as he did not have a father figure of his own growing up.
Although he resisted it for long, Ace soon accepts Whitebeard as his captain and adopted father, and befriends the rest of the Whitebeard pirates. He dedicated his life to helping Whitebeard become the next King of the Pirates. It reflects his development among the crew, as he is later promoted to Second Division Commander. The flashback concludes with him going after Blackbeard against Whitebeard's wishes, as he murdered his comrade Thatch, an unforgivable crime amongst pirates. As Ace got back into the present, he wondered why they came to his rescue despite his disobedience, to which Whitebeard responds that it was simply because he was his son.
A. Luffy joined the war at Marineford in episode 466 of the anime, titled “Straw Hat Team Arrives - The Battlefield Grows More Intense.’’
A. The war at Marineford started in episode 461 and ended in episode 489 of the One Piece anime, with the arrival of Red-Haired Shanks on the battlefield.