Kuzan

Kuzan, also known as Admiral Aokiji, is one of the anti-heroes from the One Piece game series. He is a seemingly lazy but morally upright naval officer and one of the three original admirals of the Navy (Akainu, and Kizaru). He has quite a long history with Nico Robin, considering of the tragedy that went down between them during the incidents at Ohara in the West Blue.

On his retirement, Sengoku advocates for Aokiji to succeed him as fleet admiral. Aokiji duels with Akainu for the position, but loses. Not wanting to serve under Akainu, he leaves the Navy thanks to his disillusionment with the World Government's Absolute Justice. Eventually he forms an alliance with the Blackbeard Pirates.

Having eaten the Logia-type Ice-Ice Fruit, Aokiji is capable of manipulating, creating, and transforming into ice. The strength and control of his Devil Fruit powers rivals with Akainu who fought him in a ten-day duel that left Punk Hazard in its current state.

History
Years ago on Ohara, Kuzan had caught the eye of one of the criminal archaeologists, Nico Robin. After freezing Jaguar D. Saul to death, he helped Robin escape but gave her a warning. Twenty years later, he followed Robin to Long Ring Long Land island where she was now in the service of the Straw Hat Pirates. Kuzan fought the pirates believing they shouldn't protect her. Luffy stalled the Admiral with enough time for the crew to escape.

At Marineford, Kuzan was overseeing the public execution of Portgas D. Ace. When Whitebeard sent his forces in to rescue their fellow pirate, Kuzan began to freeze the bay, and even after being shattered, was still able to repair himself. After Ace was freed, Kuzan confronted him in a battle of fire and ice, though their two elements simply cancelled each other out. As the battle at Marineford neared its end, Kuzan tried to prevent Luffy from escaping with the Heart Pirates. Eventually, Kuzan stood down.

Two years after, Kuzan partook in a duel to the death to decide the next Fleet Admiral. His opponent was fellow Admiral Akainu. After a ten day duel, Akainu arose the victor, and Kuzan resigned from the Navy, not wanting to serve under Akainu, while also forfeiting his alias and reverting to his real name.

Trivia

 * Aokiji's appearance is modeled after Yūsaku Matsuda.