Callisto is Hudson Leick
Spawned by Xena's warlord ways, the beautiful, blonde, hate-crazed Callisto has experienced various astonishing transformations. She began life as a mortal, eventually became a god in the classic Greek tradition (by eating ambrosia) and was finally transmogrified into an anget of Dahak, the vile, demonic force that threatens mortals and immortals alike. Unable to live with the pain of her own joyless existence, she maneuvered Xena into killing her, but of course came back in Xena's body. I guess Xena'll have to live with her forever!