Joe Otterson TV ReporterThe “Dune” television series prequel at HBO Max has found its new showrunner.Variety has learned exclusively that Diane Ademu-John has boarded “Dune: The Sisterhood” in the role of writer, showrunner, and executive producer. Jon Spaihts had previously been attached to run the series, but he stepped down in November 2019 to focus on writing the script for the second of the “Dune” reboot films.The show was ordered straight-to-series at HBO Max in June 2019.