Who is Mosca?

Mosca

"his Parasite," i.e. Volpone's servant. Mosca is bothersome, obsequious, and conniving. Though he is lower than Volpone in birth, Mosca is effectively the master of the scam. Volpone is the star, but Mosca is the manipulator, the one who plays the legacy hunters against each other. Like Volpone's, Mosca's greed is all-consuming, and even more than his master, Mosca operates on pure strategy, never displaying the least remorse for his deceit and chicanery.