Dragon Moon by Henry Kuttner (1915 - 1958)

Out of the dark—out of the unknown—came Karkora ... rotting the souls of the kings of Cyrena. For Karkora, the Pallid One, was a creature more loathsome than anything on earth. It was beyond good or evil, a Presence from the Outside—a shadow of which the "altar fires had whispered." - Summary by Weird Tales, January 1941