Prophecy centers entirely around the origins of the Bene Gesserit, known only as "the Sisterhood" in the show. However, there's a very simple reason for that. "The Sisterhood at its inception is not called the Bene Gesserit,

Giving space-witch vibes without space-witch powers… yet The premise of Dune: Prophecy, the latest sci-fi/fantasy lit juggernaut to hit the Max streaming service, is that it’s a show about the rise of the Bene Gesserit order.

Prophecy, the Bene Gesserit organization is under the leadership of Mother Superior Valya Harkonnen (Emily Watson), its second leader, following the passing of Raquella Berto-Anirul. Valya is a conflicted individual - she is loyal to the Sisterhood but still feels some tie to her exiled and disgraced family.