Silver Banshee
As the oldest child, Siobhan McDougal intended to perform the ancestral rite of the Clan McDougal, a ritual to keep back the dark forces under the family castle. While performing the ceremony, her uncle interrupted her, believing that only the oldest son should perform the rights. With the spell broken, Siobhan was taken into the underworld. An ancient spirit watched her suffering and took pity on her, and returned her to Earth as the Silver Banshee.
As the Banshee, Siobhan has the ability to kill anyone by screaming their name. While already possessing great mystic power, the Banshee has often clashed with Superman to gain even more power.