Bacchae are female vampires who are the followers of Bacchus. They were human women who were turned into Bacchae by being bitten by another Bacchae. Gabrielle was once turned into a Bacchae and almost became one permanently. The only way for a Bacchae to become human again is for Bacchus to be killed, and only a Bacchae can kill him. Xena allowed Gabrielle to turn her into a Bacchae and then she slew Bacchus, freeing herself, Gabrielle, and all the other Bacchae from the spell.