Alexa Luthor happens to be Lex Luthor's younger half sister with a prostitute mother,She idolizes Lex very much,She also possess extreme beauty & physical strength & intelligence.Unfortunately When she presented herself to LEX, Luthor laughed and denied her and even Humiliated her. Then admiration to Lex bacame hate and vouched to get even with him one day.In one od Lex's world destruction plan,Alexa's Mother was killed.Prompting her to to seek extreme revenge to LEX.She had shaven her head and she used her Intelligence to make Millions of dollars an created her own world destruction mechanism that sometimes jeopardized her brother's plans.LEX Was so furious and insulted and even almost killed. She was able also to get a KRYPTON AMULET that stopped either Superman or Supergirl from her plans.