Capitán Silver serves as the primary antagonist. This anthropomorphic pig pirate leads his own crew, having previously sailed under the notorious Captain Flint, and relentlessly pursues Flint's hidden treasure.

He wears pirate captain attire adorned with a skull emblem on his hat and wields a hook in place of one hand, complemented by a mustache.

Silver orchestrates the capture of Jim and his companion during their sea voyage, transporting them to Pirate Island where he sells them to a slave merchant. During this event, his crew member, the Baron, steals the treasure map from Jim. Silver presents this map to a council of pirate captains to claim authority over a ship for the treasure hunt, overriding the Baron's claim to lead the expedition himself.

Throughout the voyage, Silver persistently tries to steal the map from Kathy, Captain Flint's granddaughter, but Jim's covert aid consistently thwarts him. Silver initially plans to delay mutiny until after securing the treasure, yet his crew is incapacitated when Jim administers a sleeping potion meant for him.

A storm destroys their ship, leaving Silver, Kathy (his captive), and remnants of his crew stranded on the treasure island. Silver abandons his crew, continuing the hunt only with his monkey helmsman, Spider. As they ascend the volcanic crater housing the treasure, Jim confronts Silver. To protect Jim from Silver's aggression, Kathy reveals the final mechanism needed to access the treasure.

Acting on Kathy's information, Silver triggers the mechanism, expecting treasure. Instead, it catastrophically drains the volcanic crater lake, sweeping Silver and Spider out to sea. The draining lake exposes Captain Flint's sunken ship and the treasure within. In the aftermath, Silver is last seen pursuing Jim and Kathy's departing ship on makeshift log boats, engaged in a dispute with Spider. His portrayal remains consistently antagonistic, devoid of redeeming qualities or a paternal bond with Jim.