Sakazuki

Admiral Akainu (赤イヌ大将, Akainu Taishō formerly known as Vice Admiral Sakazuki) is an Admiral in the world of One Piece, one of only three to hold such a position and subordinate only to Fleet Admiral Sengoku.

Appearance
Like any other high ranking marine he is dressed in a simple white/grey suit with a white marine coat draped over his shoulders.

He wears a simple white marine cap and he also wears a dark grey hood that seems to be a part of a cloak he wears beneath his suit, or marine coat.

His entire face is not seen during his appearance, as it is hidden by his cap.

Personality
He believes in "Absolute Justice", going as a far as destroying the refugee ship. His logic is that if even one of the scholars of Ohara had escaped with it, the plan would've been a failure, much to the dismay of Aokiji. , who called Akainu a fool for overdoing things.

''If you are going to do a job, do it thoroughly. If even a single scholar managed to sneak on board, all the sacrifices made today would have been wasted. Evil must be completely eradicated."

-Akainu's view on destroying the ship.

Powers and abilities
As an Admiral, Akainu is able to command vast number of Marine troops that are under his rank. Most of all, he has the ability to order a Buster Call attack on any island. As the Marines' Ultimate Strike Force, He along with the other two Admirals, Aokiji and Kizaru respectively, are the three strongest individuals in the Marines.

Ohara Incident
He was known as Vice Admiral Sakazuki before his promotion. He was present at the Ohara incident, being one of the five vice-admirals, leading the Buster Call offensive. He ordered the destruction of an evacuation ship of civilians and soldiers, claiming it needed to be destroyed in case a single scholar managed to sneak on board (an action that horrified even Spandine).

Current events (spoilers)
Vice Admiral Momonga mentioned to Boa Hancock that the 3 Marine Admirals, including Akainu will lead the Marine against the Whitebeard Pirates following the announcement of Portgas D. Ace's execution. It is implied that he has answered the call to summons as Whitebeard begins to make his move.

Trivia

 * His name and other Admiral names (Aokiji, Akainu, and Kizaru), are taken from Momotaro legends (Momotaro met Pheasant, Dog, and Monkey as friends to accompany him in his journey)