Sat-Yr9 is a counterpart to Saturnyne of Earth-9 and Courtney Ross of Earth-616. The Earth-616 Ross was Captain Britian's ex-girlfriend. As Ross, Sat-Yr-9 tried to create a rift between Captain Britain and his girlfriend Meggan.
Sat-Yr-9 killed Courtney Ross in Excalibur #5, and Sat-Yr-9 assumed Courtney's identity, so all appearances of Courtney Ross after this is actually Sat-Yr-9.
Psionic: can channel psychic power through her eyes that force those of weak wills to submit to her every desire.
Leadership: Experienced and persuasive leader.
The Earth-1124 counterpart also called herself Sat-Yr-9, or Satyrnin. She was the ruler of Earth.
The Earth-9 counterpart of Sat-Yr-9 is Saturnyne.
The Earth-616 counterpart of Sat-Yr-9 was Courtney Ross.
The Earth-148 counterpart of Sat-Yr-9 is Sa'tneen.