Zephyr, also known as Z was the leader of the Neo Marines and the main antagonist of the One Piece Film: Z. He was once a Marine admiral and instructor before his resignation.
During his time as a Marine, he was very popular with his subordinates. He believed deeply in justice and heroism, having joined the Marines simply to fulfill both desires, and resigning eventually when he realized the organization was not what it seemed.
Originally a happy person, being popular among his subordinates and having created a loving family, his life changed for the worse when his wife and son were murdered by a pirate and his arm eventually severed by another, the latter who would become a Shichibukai; all of this loss and injustice led to a deep hatred towards pirates. He formed a group to take matters into his own hands and annihilate them all himself even if it also meant opposing the World Government and the Marines, and even raising a jolly roger. His strong hatred led to irrational acts such as plotting to destroy the New World to eradicate his enemies.
Despite his loathing for pirates, he did have a sense of loyalty and respect to even his enemies to the bitter end, as he gave up his life to give time for his Neo Marines and the Straw Hat Pirates to escape from Kizaru, having come to respect the latter after their final battle.
His Battle Smasher; the artificial arm/weapon he had made for him by a scientist after he lost his arm is used as decoration of his grave cross. The fate of his Neo Marines army is currently unknown, but, thanks to his actions, his subordinates Ain and Binz were able to escape from Kizaru and his Marine fleet. Though Ain and Binz mourn for their fallen leader, Kuzan (Aokiji) comforts them that he was a great man and to never forget his sacrifice.
