The already expansive “Dune” universe is about to get even bigger, “Dune: Prophecy” executive producer Alison Schapker tells CNN.

The main, and most interesting characters, in HBO's space opera are Valya Harkonnen, played by Emily Watson, and her sister Tula, played by Olivia Williams.

With their near-supernatural control over their minds and bodies, the Bene Gesserit Sisters are a force to be reckoned with, and one of the most iconic elements of the Dune univer