Red Sonja began as the Robert E. Howard one-shot character "Red Sonya of Rogatino," who was re-worked into an ongoing heroine by Roy Thomas and Barry Smith.
Though she was made a part of Conan's world, she's maintained a strong and independent visibility in the world of established franchises, if only thanks to the 1985 movie and the many outstanding renditions of the character by Frank Thorne, as seen here.
