- Boticelli: Boticelli is a blind mouse who lives in the dungeon of Dor Castle. He is a kind and gentle soul with a great love for music. Despite his blindness, Boticelli has a remarkable ability to navigate his surroundings and sense the emotions of others. He becomes Despereaux's mentor and guide, teaching him about the world and the importance of kindness.
- Roscuro: Roscuro is a rat who initially serves as the antagonist of the story. He is ambitious, cunning, and harbors a deep resentment towards humans. Roscuro is determined to become a knight, even though rats are not allowed to be knights in the kingdom of Dor. He forms an alliance with Chiaroscuro, the wicked jailor of the dungeon, to help him achieve his goal. However, as the story progresses, Roscuro begins to question his actions and eventually experiences a change of heart, leading to his redemption.