Fafhrd and the Gray Mouser are two sword-and-sorcery heroes appearing in stories written by American author Fritz Leiber. They are the protagonists of what are probably Leiber's best-known stories. One of his motives in writing them was to have a couple of fantasy heroes closer to true human nature than the likes of Howard's Conan the Barbarian or Burroughs's Tarzan.
Fafhrd is a very tall (seven feet) and strong northern barbarian, skilled at both swordsmanship and singing; the Mouser is a small (not much more than five feet) mercurial thief, gifted and deadly at swordsmanship (often using a sword in one hand and a long dagger in the other), and a former wizard's apprentice who retains some skill at magic. Fafhrd talks like a romantic, but his strong practicality usually wins through, while the cynical-sounding Mouser is prone to showing strains of sentiment at unexpected times. Both are rogues, existing within a decadent world where to be so is a requirement of survival. They spend a lot of time drinking, feasting, wenching, brawling, stealing, and gambling, and are seldom fussy about who hires their swords. But they are humane and—most of all—relish true adventure.
The stories of the two were only loosely connected until the 1960s, when Leiber organized them chronologically and added additional material in preparation for paperback publication. Starting as young men, the two separately meet their female lovers, meet each other, and lose both their lovers in the same night, which explains both their friendship and the arrested adolescence of their lifestyles. However, in later stories, the two mature, learn leadership, and eventually settle down with new female partners on the Iceland-like Rime Isle. Leiber contemplated continuing the series beyond this point, but died prior to doing so.