The Marineford arc of One Piece was, quite easily ... and it all centered around one character in particular, Portgas D. Ace, the pirate who was handed over to the navy by Blackbeard.

Sabo's existence in One Piece is revealed during Marineford, where his amnesia prevented him from joining the battle. Oda shares a hypothetical scenario where Sabo saves Ace at Marineford, but it's ...

This One Piece character causes Oda a lot of trouble. This arc was at the very end of the Summit War Saga, and it saw Luffy attempting to save his brother, Ace, from the clutches of the Government.