Origin
The Gray Mouser is an apprentice wizard turned thief and adventurer, most frequently seen in the company of his friend and partner, the barbarian Fafhrd.
Creation
Created by fantasy and science fiction author Fritz Leiber (with help from his college roommate Harry Otto Fischer).
Character Development
Mouse was an apprentice to a white wizard. After returning from a quest he had found his master dead and all his possessions burned. He discovers that the Duke had outlawed sorcery and was hunting all magic users.
Out for revenge, Mouser confronts the Duke but is outnumbered and captured. However, he is able to escape due to a distraction, and conjures up a spell that causes the Duke to fall ill. The Duke’s daughter (who was also an apprentice and who was made to help father against the wizard) discovered where Mouser was located but was followed by the Duke’s soldiers. Mouser was once again captured and was ordered to be tortured along with the Duke’s daughter, but escaped thanks to a spell. He ran into Fafhrd, while attempting to rob one of the local Thieves’ Guilds and the two formed a friendly alliance.
Homages to Fafhrd and the Gray Mouser appear in the Fables storyline Dark Ages issues 77 and 78 as “Freddy” and “Mouse”.