|The following is based on Van Buren and has not been confirmed by canon sources.|
The most powerful tribals in the American Southwest are the feared Daughters of Hecate and their slave tribe, the Vipers. Led by an aging, possibly insane woman of fearsome presence, the masked Daughters of Hecate collect tribute from almost all other tribes in the regions they control. Failure to obey the mandates of Hecate often results in crop failure, poor hunting, disease, and barren wombs. The Daughters of Hecate reserve a special hatred for Caesar's Legion because the Legion rose to power during the time of the Twisted Hair; a tribe that regularly raided other tribes for supplies and slaves. The Legion taught the other tribes to fight back and soon the Twisted Hair tribe fled. The Legion then set upon the Twisted Hair tribe, almost utterly destroying it apart from one woman, who managed to escape; in time, she became the Goddess Hecate, eponymous leader of the Daughters of Hecate.
The Hounds of Hecate are a tribe of males who serve the all-female Daughters of Hecate. The Vipers are feared warriors, mostly feared for their uncommonly excellent health and large numbers. The Vipers often travel with Daughters of Hecate, protecting them from outsiders or foolish tribes who choose to stand up to Hecate.
The "Iron Lines" resist the Daughters of Hecate and have remained largely immune to the plagues that haunt other tribes who go against Hecate’s wishes. However, the Vipers never pass up an opportunity to butcher any Iron Lines they discover.
After Hecate braided her hair in the fashion of her lost tribe, painted her face so that none could recognize her, and then left the Nursery. She traveled to the very same tribes that had rejected her and aided them with her new found knowledge of midwifery and herbal medicine. Once she gained the trust of a tribe, she began to preach her life/death/rebirth religion. She asked that young women of the tribe join her and aid her in helping all the tribes of the wasteland. Thus the Daughters of Hecate were born.
Eventually the Daughters began to decide who could marry and who could not, who could have children and who could not. Only a Daughter was allowed to deliver a child into the world and it was done in a birthing tent set apart from the rest of the tribe. No males were allowed in or near the tent. Anyone who disobeyed their edict was either stricken with impotence or their wives bore sickly children. If a Daughter was ever harmed or killed the, men of the tribe were rendered impotent until a new Daughter was assigned to them. And so the Daughters grew in power and infamy.
Unbeknown to the tribes, the Daughters were taking the best of their children and replacing them with the weak or infirm. The best of the males were taken to the Ouroboros to become warriors in the Hounds of Hecate. The best of the females were taken to become Daughters. Over the years Hecate watched as the tribes grew subtly weaker and her followers grew stronger and stronger. Soon, vengeance would be hers.
Her plan was simple. When the tribes were weak enough, her Hounds would sweep down upon them and annihilate them from the face of the earth. The same would come to pass with Caesar and his legion. When all who had wronged her were gone, she and her people would march upon paradise and reclaim it as their just reward.
The Daughters of Hecate have not appeared nor are they mentioned in any published game. They were to appear only in Van Buren, the canceled Fallout 3 by Black Isle Studios. It is not certain if they will appear in any future Fallout game.