If you want to give a strict characteristic of Gaspard Caderousse, you will obviously say that he is a greedy, drunk, and lazy man. He takes part in the plot of imprisoning Edmond, but he is not similar to the Montego or Danglars. Unlike both of the mentioned characters, Gaspard Caderousse never has a chance to meet his fortune and live the life nobody would dream for. The sense of his living and the way he survives is hidden in the occasional crimes he committed and murders. He is the man who is never satisfied with his life fully and suffers from this dissatisfaction.
Gaspard Caderousse is an example of those people who can never be completely satisfied with their life and always thinks they deserve much more than they have for the present. Gaspard could not find the success as the people from his surrounding do and their success makes him feel deep pain. In the struggle of making his position better, he is ready for any action, not paying attention to other people and their feelings. Murdering and committing the crimes is completely normal for him, and he follows his goals without any thought to stop and change something.