Aiolin Astarte was a female human engineered and trained by Doctor Cylo to replace Darth Vader as Darth Sidious' Sith apprentice. Astarte and her brother Morit Astarte were children of the Astarte line of Celanon, who had joined the Separatist cause. The Astarte line funded much of Cylo's early work. Cylo thought of them as "generally smart" and "forward facing". Fearing retribution for their allegiance during the Clone Wars, the Astartes passed their children to Cylo for training and experimentation, in the hope for redeeming themselves.