EXCLUSIVE: As HBO Max’s Dune: The Sisterhood (wt) moves into production, series creator and writer Diane Ademu-John is stepping down as co-showrunner. She will remain creatively involved in the prequel as executive producer but will focus on other commitments. Veteran TV writer-producer Alison Schapker, who has served as co-showrunner with Ademu-John, will now be the sole showrunner for the series.