Akainu is the current Fleet Admiral of the Marines, succeeding the previous fleet admiral, Sengoku.
He possesses tremendous physical strength, as shown when he pinned Whitebeard’s giant bisento down to the ground with just one leg. Furthermore, he was the one who emerged victorious from the ten day duel between him and Aokiji for the position of the fleet admiral.
Akainu’s background is renowned, especially among the stronger figures in the New World, striking fear into the hearts of pirates and marines alike. After Van Augur identified Akainu aboard a marine ship for negotiations, Blackbeard immediately fled, knowing the consequences of battling against him, even though Blackbeard had gained the powers of the Gura Gura no Mi, and had strengthened his crew with several of Impel Down’s most powerful criminals.