Mentioned in The Colour of Magic, Weasel is Bravd the Hublander's partner. He is the short and stealthy member of the duo, using his brown cloak as a basic camouflage. He is noted for having taken (in this order) a magic staff, a belt of moon jewels and his life from the Archmage of Ymitury. Bravd and Weasel are parodies of the popular sword & sorcery heroes Fafhrd and Gray Mouser created by Fritz Leiber, Bravd being very similar to Fafhrd and Weasel having some affinity with Gray Mouser.
He and his partner Bravd are the first characters in the Discworld to be named and described.