Hack

Hundredth Dan Hack is a Japanese soldierfish fishman and member of the Revolutionary Army. He went to Dressrosa to investigate the arms trafficking there and competed at the Corrida Colosseum for the Mera Mera no Mi. Hack is a calm and proud person, and follows a dream where a path of friendship may be formed by fighting. For that reason, he will continue fighting. He finds fighting battles to be honorable and thus, dislikes those who show a lack of respect toward a fight such as Bartolomeo.

He is very honorable and dislikes attacking an opponent from the back, but he will do it if said opponent is not worthy of his respect, as he did to Bartolomeo, who was urinating on the side of the fighting ring and was, in Hack's opinion, not taking the battle seriously. As a fishman, he is at least ten times stronger than an average human, and twice that in the water. However, as he is taking part in the Corrida Colosseum fights, a location in the New World, as well as from the demonstration of a high-level Fishman Karate attack, it is implied that Hack's much stronger than that. He was able to stop an assault from a large gladiator by grabbing his opponent's spiked club, with the man commenting that he was unable to move his weapon in Hack's grip. Hack is an instructor in Fishman Karate, in comparison to Koala's status as assistant instructor. He uses Fishman Karate to attack his opponents with great strength. Hack is a Fishman Jujutsu martial artist, although he has not been seen using any techniques.