After Ace’s death, Sabo, who had amnesia from his incident, regains his memory and meets with his surviving brother during the Dressrosa Arc of One Piece, revealing he is alive and well to Luffy.

Oda shares a hypothetical scenario where Sabo saves Ace at Marineford, but it's considered a dream by Luffy and Sabo. Sabo's presence at Marineford would have eased Luffy's emotional burden and ...