This is a series.
Fafhrd is a tall, strong northern warrior, while the Gray Mouser is a smaller and more cautious swordsman with experience in thievery and magic. Their contrasting personalities form the central dynamic of the series. The stories commonly take place in the city of Lankhmar and the surrounding regions, where the two protagonists work as mercenaries, thieves, explorers, and occasional wanderers. Their activities bring them into contact with sorcerers, supernatural beings, rival adventurers, criminals, monsters, and various political and religious powers. Their motivations are often practical rather than heroic, involving money, survival, curiosity, revenge, or personal loyalties. Leiber began publishing stories about the characters in 1939, and continued developing them over several decades. The series is associated with the development of modern sword-and-sorcery fiction, particularly through its combination of adventure, humor, urban settings, magic, and flawed protagonists. Unlike more traditional heroic fantasy, Fafhrd and the Gray Mouser are frequently motivated by self-interest and make decisions that lead to unintended consequences. The series became an important literary reference for later fantasy role-playing games, including Dungeons & Dragons. Its influence can be seen in the idea of a small group of adventurers with different skills undertaking dangerous journeys, exploring ruins and cities, encountering monsters and supernatural forces, and pursuing treasure or other personal objectives.