"Z 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 as just as he had hoped. According to Garp, Z was the strongest believer of justice.

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 later all but two of his cadets killed and his right arm severed by another, the latter who would become a Shichibukai. Such loss and injustice led to a deep hatred towards pirates, and after he left the marines he formed a group to take matters into his own hands and annihilate them all, even if it also meant opposing the World Government and the Marines. His hatred led to irrational acts such as plotting to destroy the New World to eradicate his enemies at the cost of countless innocent lives.

He believed that pirates must be eliminated on sight, and that merely imprisoning them was ridiculous. His loathing was so strong that he would go to the extremes to achieve his agenda, whether physical, like stealing a powerful weapon from the Marines, or moralistic, like raising a jolly roger himself. He also claimed that even if Monkey D. Luffy defeated him, no-one would recognize him because he is a pirate, so firm is his belief in the worthlessness of pirates.

Z heavily believed in the power of dreams. His ultimate ambition was to end the Great Age of Piracy, which he planned to achieve by destroying the three geographic Endpoints of the New World with the Dyna Stones and releasing enough magma to utterly destroy the fabled One Piece, a plan he called the Grand Reboot. Despite his claims, he appeared to be aware that his plan would fail, and he told Luffy that he was simply happy that his plan went that far.

Z exhibited bravery to the point of fearlessness throughout his life. Even at his old age, he faced a whole elite marine platoon led by admiral Kizaru without hesitation or concern. During his earlier battle against Kizaru at Firs Island, he admonished Kizaru as having become overconfident since he became an admiral, a rare attitude to take against such a formidable opponent.

Despite his loathing for pirates, Z had a great sense of honor, loyalty and respect to everyone, even his enemies, and was noble in character to the bitter end; his last act, after having fought evenly with Luffy to a standstill, was to give up his life to buy time for his Neo Marines and the Straw Hat Pirates to escape from Kizaru, having come to respect the latter after their final battle.

Lastly, Z also loved alcohol, as shown during his encounter with Kuzan. His favorite drink is Jerez, of which he drank a bottle prior to his last fight with Luffy."