John Silver is the primary antagonist in the anime adaptation of *Treasure Island*. He runs the Spy Glass tavern in Bristol and is initially recommended as cook and quartermaster for the Hispaniola voyage. Despite a missing leg requiring a crutch, he displays significant physical agility and strength. Silver cultivates a genial and trustworthy facade, bonding with Jim Hawkins during the voyage and acting as his mentor. This connection complicates Jim's view when Silver's true nature surfaces.

Formerly the right-hand man of the notorious pirate Captain Flint, Silver orchestrates a mutiny aboard the Hispaniola, recruiting crew members from Flint's original gang. He commands the mutineers through a potent mix of charisma and intimidation. Upon reaching Treasure Island, Silver openly betrays the officers, triggering violent confrontations. He takes Jim hostage to leverage the treasure map, yet later intervenes to save Jim from being killed by fellow pirates during a leadership dispute—an act reflecting pragmatic self-interest and an ambiguous lingering bond.

Silver's cunning manifests in his tactical adaptability, shifting between negotiation, manipulation, and open conflict as circumstances demand. Ultimately, he escapes justice by stealing a portion of the treasure and fleeing alone, abandoning his crew. His fate remains unresolved, consistent with his morally complex identity defined by ambition and relentless self-preservation.