"Red Moon of Zembabwei" is a short story by L. Sprague de Camp and Lin Carter featuring the fictional sword and sorcery hero Conan the Barbarian created by Robert E. Howard. It was first published in the July 1974 issue of the magazine Fantastic, and was first appeared in book form by Ace Books in the paperback collection Conan of Aquilonia in May 1977, which was reprinted several times through 1994. The first British edition was published by Sphere Books in October 1978.
Following his defeat of the sorcerer Thoth-Amon in Stygia in "Black Sphinx of Nebthu," King Conan of Aquilonia pursues his arch foe to the kingdom of Zembabwei. Thoth-Amon has taken refuge there with Nenaunir, a wizard-ally who has usurped the throne from his own twin brother. Conan, who has entered the city to negotiate his enemy's surrender, is ignorant of this state of affairs until he finds himself thrown in the dungeon with the rightful king, who has been deposed and tortured by Nenaunir. Murzio, a spy from the Aquilonian army, is able to slip through the sewers of Zembabwei to reach the dungeon, but is unable to release Conan. But he is able to open the gates of the city to the Aquilonian army. In the meantime, Conan and Conn are to be sacrificed to the evil serpent-god Set, or Damballah, as the deity is known in Zembabwei. Prince Conn saves the day by killing Nenaunir and thus nullifying the earthly materialisation of Damballah. Having lost his sanctuary, Thoth-Amon flees south on a flying wyvern.