Gaspard Caderousse is a supporting character in the narrative who originally worked as a sailor alongside Edmond Dantes. In his youth, he appeared to support the relationship between Edmond and Mercédès. Many years later, he reemerges as a disheveled and impoverished figure, having fallen into alcoholism and a diminished social standing. His physical appearance is distinctive and somewhat shabby; he is a very short man with green hair, a green mustache, and a notably large nose, typically dressed in worn and dull clothing.

The personality of the older Gaspard is defined by sleaziness, greed, and profound cowardice. He holds no genuine loyalty to anyone, acting entirely out of self-interest. His primary motivation is financial gain, and he has no qualms about selling information to the highest bidder, including secrets about the past conspiracy that led to Edmond Dantes imprisonment. Despite his involvement in the plot against Edmond, he is not a primary target of the Count of Monte Cristo's revenge, possibly because he was merely an opportunist rather than a mastermind, or because his current miserable state is considered punishment enough.

His role in the story is that of an informant and a minor antagonist who provides crucial information to multiple parties for a price. When Fernand Mondego seeks him out for details, Gaspard demands a large sum of money before divulging anything. Similarly, he sells vital information to the journalist Beauchamp. He is also present at a false funeral orchestrated by the Count, where he reunites with his old acquaintances Jullian Danglars, Fernand Mondego, and Gerard de Villefort. At this event, he nervously insists he did not send the invitations and expresses his superstitious belief that Edmond Dantes has returned from the grave to exact revenge on all of them.

In terms of key relationships, Gaspard is connected to the primary conspirators from Edmonds past—Danglars, Mondego, and Villefort—but he exists on their periphery as a less significant and more pathetic figure. He is also linked to Benedetto, as both are revealed to have bounties on their heads and are fleeing from the law by the end of the series. His development is minimal, as he remains a consistently greedy and cowardly character. During Fernand Mondego's hostile takeover of Paris, his cowardice is on full display when he gleefully attempts to flee with his bag of money, only to have it knocked from his hands, leading to a panicked scramble to retrieve his cash. Regarding notable abilities, Gaspard possesses no physical or combat skills of note. His sole talent lies in manipulation and leveraging his knowledge of the past, effectively knowing how to pressure and extract payments from desperate individuals like Mondego.