The Marineford arc of One Piece served as the finale not only to the Summit War Saga but also to the pre-timeskip era of the manga as a whole. At the time, it was easily the most climactic arc the series had seen yet. Luffy, a ragtag crew of rescued inmates from Impel Down, and the Whitebeard Pirates — the most powerful pirate crew in the world — went to war with the Marines, including the admirals and the warlords, all to save Luffy's brother, Ace, from being executed.
Source：https://www.cbr.com/one-piece-marineford-arc-greatest-characters/
