Octy, who is known in the original Japanese version as Hatchan, is an octopus fish-man and an officer of the Arlong Pirates who appears as a supporting character in the television special One Piece Episode of Nami: Kōkaishi no Namida to Nakama no Kizuna. He was born in the fish-man district of Fish-Man Island, where he grew up alongside several of his future crewmates, and he once served under Fisher Tiger as a member of the Sun Pirates before that crew disbanded and he followed Arlong. In the special, which retells the conflict at Arlong Park with a focus on Nami, Octy serves as one of Arlong's officers and takes part in the crew's domination of Cocoyasi Village and its coercive arrangement with Nami. His most significant role in the story is his duel with Roronoa Zoro, the swordsman of the Straw Hat crew; although Zoro fights while weakened by a fever and severe blood loss from an earlier injury, he ultimately defeats Octy.

In terms of personality, Octy is cheerful, good-natured, and simple-minded, and he is easily deceived, which frequently places him in comical situations. He is not driven by the same intense hatred of humans that defines his captain, and he behaves politely even toward his opponents, such as when he first addresses Zoro with respect. However, as a loyal member of the Arlong Pirates, he can act cruelly toward humans when following the crew's orders, reflecting the prejudices of the group he belongs to. His motivations during the Arlong Park story are mostly tied to his duties within the crew, and he lacks the personal ambition to terrorize or rule over humans that Arlong possesses; he functions primarily as a follower who carries out his assigned role as an officer.

Octy's key relationships are shaped by his position in the Arlong Pirates. He is loyal to his captain, Arlong, and works alongside the other officers Kuroobi and Chew, who were also his childhood friends and fellow members of the Sun Pirates. His battle with Zoro is the most important relationship shown in the special, and although the two begin as enemies, Zoro's victory marks the point at which Octy begins to separate himself from the Arlong Pirates' ideology. His continuing story in the broader One Piece series shows his development beyond this role: after the rest of the Arlong Pirates are arrested, Octy is the sole member to escape. He eventually abandons piracy for a peaceful life and opens a floating takoyaki restaurant, becoming a friendly and helpful figure who reunites with the Straw Hat crew and befriends the mermaid Camie. In this way, his arc moves from antagonist to a redeemed former pirate who finds a new purpose outside of violence.

Octy's abilities stem from his octopus physiology. He has six arms, which allow him to wield six swords simultaneously in a fighting style called the Six-Sword Style. Among his techniques are the six-fisted Octopus Punch, the Takoyaki Punch, and the ability to spit black ink to blind opponents, as well as the use of the suckers on his hands to grip objects and weapons. As a fish-man, he possesses superhuman strength, speed, and durability, and he is fully capable of fighting underwater. Standing roughly seven feet tall, he has an imposing physical presence, although his lack of intelligence and trusting nature often undercut his considerable skill as a swordsman.