Jack’s infamy stems from his allegiance to the Beasts Pirates and his status as one of Kaidou’s most trusted lieutenants. His brutal methods and unrelenting nature made him a feared figure, particularly during his reign over Kuri in Wano Country. As a giant grouper fish-man, Jack possesses extraordinary physical strength and the ability to survive underwater, giving him an advantage in naval combat.

Jack was first mentioned during the Punk Hazard incident when viewers of Caesar Clown’s broadcast reported Caesar’s capture to him. His subsequent actions, including the invasion of Zou and his involvement in the Raid on Onigashima, solidified his role as a key antagonist in the One Piece narrative.

Jack is an enormous, muscular fish-man with long, wild hair and a distinctive set of horns protruding from his head. He typically wears a fur-trimmed coat, which emphasizes his role as a fearsome enforcer for the Beasts Pirates. His weapon of choice is a pair of scythe-like tusks attached to his hands, which he uses with devastating efficiency in combat.

Jack is ruthless, aggressive, and fiercely loyal to Kaidou and the Beasts Pirates. His unyielding determination often borders on recklessness, as seen in his relentless pursuit of his goals regardless of the cost to himself or his crew. While Jack’s brutality makes him a feared figure, it also highlights his unwavering commitment to his mission, even in the face of overwhelming odds.

Despite his harsh demeanor, Jack’s loyalty to his allies is evident, particularly in his interactions with King and Queen, where he is often mocked for being the youngest and least experienced of the All-Stars.

Zou Arc
Jack serves as the main antagonist of the Zou Arc, leading a brutal invasion of the Mokomo Dukedom in search of the samurai Raizo. His actions during the invasion left the Mink Tribe devastated, as he unleashed a poisonous gas weapon, Koro, to force their surrender. Despite his overwhelming strength, Jack was ultimately repelled when Zunisha, the giant elephant that carries Zou, struck him down, destroying his fleet and sending him into the sea.

Wano Country Arc
Jack reemerges as a major antagonist during the Wano Country Arc, playing a key role in defending Kaidou’s territory against the Ninja-Pirate-Mink-Samurai Alliance. He fights against the Mink Tribe once again during the Raid on Onigashima, engaging in a fierce battle with Inuarashi and Nekomamushi. Despite his strength, Jack is ultimately defeated by the Sulong-transformed Minks, marking a significant blow to Kaidou’s forces.

• Kaidou
  As one of Kaidou’s most trusted lieutenants, Jack demonstrates unwavering loyalty to his captain, often taking on the most dangerous missions to prove his worth.

• King and Queen
  Jack’s fellow All-Stars frequently mock him for being the youngest and least experienced, though they share a mutual respect for each other’s strength.

• Mink Tribe
  Jack is despised by the Mink Tribe for his invasion of Zou and the devastation he caused, particularly his use of poison gas against their people.

• Nekomamushi and Inuarashi
  Jack’s rivalry with the Mink rulers is a central conflict in both the Zou and Wano Country Arcs, culminating in his defeat at their hands.