The She-Demon was one of the children of Echidna and Typhon. She once turned Iolaus to stone. He, along with all her other victims, was restored when Hercules killed the She-Demon (HTLJ "The Wrong Path"). Typhon told Hercules that the She-Demon had a beautiful voice and was a singer (HTLJ "Cast a Giant Shadow").
When Iolaus' grandmother, Leandra, reappeared after being missing for 50 years in Syllabus, she told him to beware the She-Demon (HTLJ "Love Takes a Holiday"), suggesting that she was over 50 by the time Hercules defeated her.
The She-Demon possessed the upper body of a beautiful human female with attractive body shape and fair complexion, and the lower body of a serpent with rattle snake-shape tail . In order to maintain her disguise and lure men into her trap, she often wore a long white frock dress to conceal her lower half and thus hide her true nature. Her serpent-like body granted her enhanced agility and maneuverability, allowing her to cover ground very quickly, and her tail was partially prehensile, allowing her to lash out with it like a weapon.
The She-Demon had the power of petrification and could turn others to stone by striking them with the tip of her tail. She was not immune to her own power, and was defeated by Hercules when he tricked her into striking herself with her own tail. The She-Demon's petrification power wore off of her victims once she became petrified.
The She-Demon was rumored to have been a follower of Hecate, as she was said to have been sacrificing the souls of those she petrified to the goddess.
- The She-Demon was immortalized as an action figure by ToyBiz.
- The She-Demon is said to be sacrificing souls to Hecate when she petrifies her victims, however they seem no worse for the wear when her spell is eventually broken by her death. This suggests that either the souls were taken from Hecate upon the She-Demon's death, or her affiliation with Hecate was simply an unsubstantiated rumor spread by the villagers.
- The She-Demon was the second known child of Echidna to be killed by Hercules causing her to seek revenge on Hercules.
- Although her appearance suggests a modern interpretation of Lamia, the She-Demon's powers and story more closely mirror those of Medusa. Lamia was a queen from a lesser-known Greek myth, a lover of Zeus who ran afoul of Hera, who was described as having a serpent's tale in 19th-century poetry. Another inspiration for the She-Demon's appearance might have been the naga - an East Indian mythological creature.
- In the original myths, Echidna was half-woman and half-serpent, closer to how the She-Demon was portrayed here.
- In fan fiction, the She-Demon is often given the name Lamia, in reference to her overall appearance.