Astra was recruited by Magneto to be in his original Brotherhood of Evil Mutants but when her affections for him were not returned she left the group and swore revenge. She used her powers to travel across the universe and collected many different alien technologies which could aid her in her task. Once Magneto was rendered comatose by Xavier and Asteroid M destroyed, she retrieved him restored his memories and cloned him in order to create Joseph, a more powerful and younger version of Magneto. She commanded Joseph to attack Magneto, but when Magneto was about to lose he used his helmet to hit Joseph´s head leading him to an amnesic state. Joseph escaped from Astra, but was found later by Sister Maria de la Joya, who took care of him.
Astra appeared again some time later in order to recover his creaton, so she abducted the new renewed Joseph and showed him how he was conceived to be the new Magneto.
The Magneto War
Joseph and Magneto battle in a final confrontation, Magneto threats the world with a global attack and the X-Men and Joseph opposed him. At the end Joseph sacrificed himself to reorder the world Magnetosphere. So, Astra escpaed the action when she saw how his creation is destroyed and Magneto was named as the new ruler of Genosha.
Magneto: Not a hero
Astra has reappeared, years later, with a new incarnation of the Brotherhood with Joseph in charge. Joseph uses Magneto´s costume and kills a group of anti-mutant humans and now Magneto is on the eyes of the Avengers.
Is revealed how she travelled back to Magneto´s citadel and find a way to recreate Joseph without memories and reprogrammed him to hate Human kind. With this new programation Joseph created the new Brotherhood proclaming himself as Magneto. Astra is no longer in charge of the situation and became the pet of Joseph.