Billy Bones appears in the 1978 anime adaptation of Treasure Island, known in Japanese as Takarajima. His background establishes him as a former crew member of the infamous Captain Flint, having served as his first mate. At some point, he came into possession of a treasure map that leads to Flint's hidden fortune on a remote island, a secret he guards obsessively. When he first appears, he is a rough and weathered figure, lodging at the Admiral Benbow Inn run by young Jim Hawkins and his mother. He is a blond man with brown eyes and shoulder-length hair, bearing visible marks of a violent past, such as scars on his face.

His personality is defined by volatility and deep-seated paranoia. Billy Bones is a severe alcoholic, frequently drinking rum to excess, and when intoxicated, he becomes loud, aggressive, and belligerent, often driving other patrons from the inn with his sword-waving antics and sea shanties. However, beneath this rough exterior lies a man living in constant fear. He is haunted by the threat of other pirates, particularly a one-legged man, who are hunting him to claim the treasure map. This paranoia makes him secretive and perpetually on edge, yet he is not portrayed as a true villain. When sober, he can be standoffish but is rarely cruel, especially toward Jim and his mother, showing them a grudging respect. This duality reveals a kind heart that becomes most apparent in his bond with the young protagonist.

Billy Bones serves a crucial role in the story as the catalyst for the entire adventure. His arrival at the inn disrupts the ordinary life of Jim Hawkins, introducing him to the dangerous world of pirates and buried treasure. He is not a long-lived character; his presence is concentrated in the opening episodes. His primary motivation is to evade his pursuers and protect the secret of the treasure map he possesses. He lives in a state of constant anxiety, knowing his former associates are closing in on him. His deep-seated fear is realized when he suffers a fatal stroke, a consequence of his severe alcoholism and the immense stress of his situation. In his final moments, he entrusts the precious map to Jim, setting the boy on his path to Treasure Island.

The most significant relationship Billy Bones forms is with Jim Hawkins. Despite his gruff and intimidating demeanor, he enlists Jim's help, asking the boy to keep watch for a one-legged sailor. He pays Jim for his service and, over time, a bond of trust and respect forms between the unlikely pair. This connection is poignant, as the dying pirate finds a measure of solace in the boy's honesty, and Jim, in turn, sees the frightened man behind the pirate's bravado. Billy's death and his legacy of the treasure map directly shape Jim's motivations and courage for the rest of the series. His presence looms over the narrative, as the one-legged man he feared is later revealed to be the charismatic yet ruthless Long John Silver, making Silver indirectly responsible for the fear that plagued Billy's final days. Billy Bones himself does not undergo significant development, as his arc is brief and tragic, but his actions irrevocably change the course of Jim's life. His notable abilities lie not in physical prowess, as his health is ruined by drink, but in his survival skills and deep knowledge of pirate life. More than anything, his most defining trait is his obsessive, fearful determination to hold onto his secret until the very end.