Thulsa Doom first appeared (as Thulses Doom) at the end of the short story "Delcardes' Cat" by Robert E. Howard, which featured the character Kull as the protagonist. Howard later edited the text to include foreshadowing/references to Thulsa Doom (as he had been rechristened) throughout the story and changed the title to "The Cat and the Skull" to reflect this. Editor Patrice Louinet speculated that this change was because Howard had originally intended Kuthulos (whom Doom impersonated in this story) to be the actual villain before coming up with Thulsa Doom near the story's completion. This version was submitted to "Weird Tales" in 1928, but it was not accepted. The story did not see print until 1967 in the paperback "King Kull" published by Lancer Books.