Not much is known about his Histroy other the he was a vice admiral.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).
Akainu has a square-shaped face with hollowed cheeks. There also appears to be a tattoo on the left side of his chest, but it is largely obscured from view by his shirt. However, from what can be seen, the tattoo appears to have many images of flowers integrated into its design. He is also just as tall as the other Admirals, Aokiji
and Kizaru .Twenty years ago he wore a simple white Marine cap under a dark gray hood that seemed to be a part of a cloak he wore beneath his suit, or marine coat. Like any other high-ranking Marine, he was dressed in a simple white/gray suit with a white marine coat draped over his shoulders. His entire face was not seen during this appearance, as it was hidden by his cap.
Akainu is a firm believer in "absolute justice ", and is ruthless in his maintenance of it. Of the three admirals , he is the only one who has had a dead-serious disposition at all times and also has the most ruthlessness.
Akainu's beliefs led him to go as far as destroying a refugee ship simply because of the minuscule possibility that a scholar could be hiding on board. His logic is that if even one of the scholars of Ohara had escaped with it, the mission would've been a failure, much to the dismay of Apkiji who called him a fool for overdoing things. Akainu takes his extremist attitude as far as to kill anyone who doesn't share his point of view, as he attempted to kill Coby for his plead to stop the war. Additionally, he has no tolerance for Marines who desert their posts and even appeals of wanting to return to families instead of dying does not sway his sympathy, the only consolation he does offer is that they should not dishonor their families by running away .To Akainu, any marine who is not willing to fight for "Justice" is not worthy to be called a Marine.
Despite his status as Admiral, Akainu is also known to use underhanded tactics and is willing to lie or misdirect his enemies in order to achieve results. So far Akainu's manipulations have been incredibly successful such as he managed to insulting Whitebeard to get Ace angry enough to stop his attempt at escape. He finds people who attempt to interfere with him as nothing more than irritating obstacles. Furthermore, he seems in many ways unthreatened by older legends and comments on this when Whitebeard claims to his men not to be intimidated by Garp, while Akainu says that he and Garp are of the same generation and promptly attacks him.
Abilities and Powers
He is a very skilled manipulator, using his knowledge of his opponents to manipulate them into doing what he wants. He feigned sympathy to Squardo , and used his hatred of the late Pirate King to influence him into betraying his loyalty to Whitebeard. He also used Ace's devotion to Whitebeard to his advantage, insulting Whitebeard in order to provoke Ace into attacking him, and ultimately killing the young pirate by aiming for his younger brother.
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.
Being one of the strongest characters amongst One Piece, Admiral Akainu is able to take on against Whitebeard all by himself and must have an incredible amount of durability by the fact that not even two quale punches from Whitebeard were able to keep him down which. His durability also extend to Haki attacks since it took Whitebeard's Haki to actually affect him.His presence alone was enough to make Blackbeard and his crew flee, even after Blackbeard had gained the powers of the Gura Gura no Mi.
Akainu possesses the magu magu no mi, a logia-class devil fruit which grants him the ability to transform his body into magma and manipulate it at will. As a Logia, Akainu can let physical attacks pass through him without injury and can only be wounded with the use of haki. Apparently, Akainu is aware of Haki and found some way to avoid Haki attacks, even after Marco and Vista sliced him in the neck with Haki infused attacks.
Akainu's signature method of offense is to transform his fist into magma and expand it with a forward motion (in the anime is also shown that Akainu can launch his magma fists, much like a rocket punch). When it comes to travel, Akainu can move at extremely high speeds by launching himself like an actual volcano blast towards his target and can even melt solid earth and rock to make tunnels to move underground. Just by forming an attack, the heat coming off of his body has been shown to melt enemy weapons around him. He has been shown to repeatedly pierce through the bodies of his adversaries with ease using his power, and was responsible for the complete destruction of the Moby Dick. Along with the incredible corrosion and temperatures, the magma-based attacks also carry highly explosive properties; one attack is enough to cause an explosion capable of inflicting tremendous damage throughout the entire battlefield