Originally, Satan Girl was an evil duplicate of Kara Zor-El created by Red Kryptonite in Adventure Comics 313, 1963. She attempted to kill Supergirl's fellow female legionnaires so she could sustain her independent existence. Satan Girl reappears in Legionnaires #17 (August 1994), as one of the time anomalies created by the events of Zero Hour.The storyline in Supergirl Vol 5.