TV Special
Description
Byojack, older brother to Byrnndi World and vice-captain of the World Pirates, contracted an unknown childhood disease that halted his physical growth. This resulted in permanent frailty and weakness, though it was not life-threatening, as he lived past 80. Despite his condition, he shared dreams of adventure with his brother and convinced World to explore the seas. World insisted on taking Byojack along, leading to the formation of the World Pirates.

As a child, Byojack appeared thin due to his illness and wore simple clothing. In adulthood, he remained short and frail, often seen sitting on World’s shoulder. He wore a horned helmet with one broken horn, modified by World to accommodate him, and a green coat. Byojack opposed his captain’s increasingly destructive plans, advocating for their original goal of freedom and adventure. He valued crew loyalty and expressed concern over World’s disregard for their safety, especially after World’s imprisonment shifted his focus to revenge.

Lacking combat strength, Byojack served as an information specialist. He monitored Marine and World Government communications using multiple Den Den Mushi, providing critical intelligence and advising World, demonstrating strategic insight. During the crew’s early years, he witnessed World’s descent into violence, which attracted government attention. Thirty years before the events of "3D2Y," the Marines and rival pirates besieged the World Pirates. Cipher Pol agents infiltrated, persuading lower-ranking members to betray World. Byojack and three officers fled during the chaos to avoid capture, though World interpreted this as abandonment.

Following World’s escape from Impel Down, Byojack reunited with him. He grew alarmed as World prioritized revenge over the crew, endangering them during attacks on World Noble ships. Byojack intercepted transmissions about the Marines mobilizing the Warlords against them and objected to World’s plan to kidnap Boa Hancock. When World captured her sisters instead, Byojack pleaded with him to reconsider, invoking their shared past.

During the confrontation with Luffy and Hancock on the World Pirates’ ship, Byojack reported the Marines' arrival. World dismissed him as a tool, prompting Luffy to save him from an attack. After Luffy defeated World, Byojack urged his brother to abandon the cannon and restart their adventures. World ignored him, firing the weapon despite his injuries. Mihawk destroyed the projectile, and World died from exertion. Byojack remained beside him as the ship exploded, his fate left unknown.