John Giant

Vice-Admiral John Giant (ジョン・ジャイアント中将 Jon Jaianto Chūjō) is one of the Marine officers in the Marine Headquarters.

Appearance
John Giant is a giant, and towers a regular soldier by several times. He wears a red hat with the Marines' symbol on it, and a variation of the standard Marine coat with yellow colorings, red borders, and medals adorned on the left side. Unlike other high-ranking Marines, he wears his Marine coat with his arms in the sleeves. Underneath that, he wears an orange shirt. Overall, he appears to be a well decorated marine.

He also wields a katana that fits his size, slung over his shoulder.

Post Arlong Arc
During the announcement of Luffy's first bounty. At that time he was giving a speech regarding the "Justice". He is currently the only seen senior officer of the headquarters and who is assigned to lead the dispatchment of the Buster Call fleet, when needed.

Enies Lobby Arc
He was seen again, shouting orders after the Buster Call was signaled. When the signal was received a report was given directly to him, implying his high status at the headquarters,as well as the fact that he has the powers to command others of the same rank (via the five Buster Call vice-admirals).

Marineford Arc
When the execution of Portgas D. Ace was announced, John reported to the summoning of the Marines to reinforce Mariejois. Three hours before Ace's execution, he is seen rallying the 100,000 troops on Marineford for the upcoming battle.

Trivia

 * His name and rank are revealed in One Piece Yellow.
 * John Giant was the second giant to be a Marine, the first being Jaguar D. Saul. Incidentally, they both were also Vice Admirals.