Portgas D. Ace

Portgas D. Ace, born as Gol D. Ace and nicknamed "Fire Fist" Ace, was the sworn older brother of Luffy and Sabo, and the son of the late Pirate King, Gol D. Roger and his lover, Portgas D. Rouge.

Ace was adopted by Monkey D. Garp as wished by Roger to him before his birth. Ace was the 2nd division commander of the Whitebeard Pirates and one-time captain of the Spade Pirates. He also is the central character from Ace's Great Blackbeard Search Cover Page Serial.

Hunted by the World Government for his lineage, Ace was captured and sentenced to death, which resulted in the Summit War of Marineford in an all out clash of powers. Ace was freed, but he sacrificed his life to protect Luffy from Akainu.

Ace's death ultimately proved to be the catalyst leading to Luffy training for two years to become strong enough to protect his friends, paving the way for the second half of the series.