In the World of Greyhawk campaign setting for the Dungeons & Dragons roleplaying game, as well as in the game's default pantheon of deities, Nerull is the Flan god of death, darkness, murder, and the underworld. He is known as the Reaper, the Foe of All Good, the Hater of Life, and the Bringer of Darkness. His symbol is a skull and scythe.
Nerull was first detailed for the Dungeons & Dragons game in "The Deities and Demigods of the World of Greyhawk" by Gary Gygax in Dragon #71 (1983). Nerull was subsequently detailed in the World of Greyhawk Fantasy Game Setting (1983), and in Greyhawk Adventures (1988).
Nerull was one of the deities described in the From the Ashes set (1992), for the Greyhawk campaign, and appeared again in Greyhawk: The Adventure Begins (1998).
His role in the cosmology of the Planescape campaign setting was described in On Hallowed Ground (1996).