Callisto was the leader of a small band of outcast mutants sometimes referred to as The Omegas or Omega Gang.
After the mutant cure was created, The Omega Muties allied with The Brotherhood of Mutants. Callisto seemed to dislike Storm, who she attacked repeatedly. She was eventually electrocuted by Storm during their climactic battle on Alcatraz Island. It was likely she died there.
Powers and Abilities
X-Factor Detection: She was able to psionically sense the presence and power level of other Mutants.
Superhuman Speed: She is able to run much faster than a normal human being.
Speed Physiology: Callisto's body was adapted to the rigors of high-speed movement. Her cardiovascular and respiratory systems were likely many times more efficient than those of a normal human being.
Normal human female who engages in regular exercise.