EXCLUSIVE: This is the Wayward Sisters core cast Supernatural fans had been wishing for — Briana Buckmaster, Kathryn Newton and Katherine Ramdeen from the original series have closed deals to join the proposed Supernatural spinoff toplined by fellow Supernatural standout Kim Rhodes. Also cast in the project, which is being developed as a planted spinoff and will have a backdoor pilot airing as an episode of Supernatural‘s upcoming 13th season, is young actress Clark Backo (Designated Survivor), who would play a newly created character.

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Wayward Sisters, from a quartet of Supernatural writers-producers — showrunners Andrew Dabb and Robert Singer as well as Phil Sgriccia, Robert Berens — tells the story of Sheriff Jody Mills (Rhodes) and a group of troubled young women — all orphaned by supernatural tragedy — these “wayward sisters” emerge as a formidable force against the supernatural, under Mills’s training and protection. Unlike the original series, which centers on a biological brothers, Wayward Sisters is about a sisterhood of girls in a foster family.

Lending Jody a hand will be series fan-favorite Sheriff Donna Hanscum (Buckmaster), a relative novice to the hunter’s life, but a close friend who Jody can confide in.

Newton will reprise her role as orphan Claire Novak, who was introduced to the supernatural world when her father became the vessel for the angel Castiel (Misha Collins). Now, a gifted hunter, she lives with Jody, but struggles against her rules.

Ramdeen is runaway Alex Jones, who had been put under Jody’s care. She was rescued by the Winchesters from a family of vampires who used her as a lure for unsuspecting humans. Traumatized by the violence, she has resolved not to hunt…until a threat emerges in Sioux Falls that threatens her new family.

Backo will play Patience Turner, a new member of the Wayward Sisterhood. A high school over-achiever, Patience’s life is turned upside down when she discovers she’s a powerful psychic, a gift she inherited from her estranged grandmother (and season one Supernatural character) Missouri Moseley. Hunted by dark forces for her power, Patience finds refuge with Jody and her wayward family.

Loretta Devine, who played Kansas psychic Missouri Moseley in a memorable appearance as a Winchester family friend in the season one episode “Home,” will return to Supernatural for an episode from the upcoming season.

Written by Berens and Dabb, Wayward Sisters hails from Warner Bros TV, which produces Supernatural. Dabb, Singer, Sgriccia and Berens executive produce.

Jody, Claire, Alex and Donna have been the dream quartet of characters of a spinoff fans had been rallying for, dubbed Wayward Daughters. Named in part after the title of the Kansas song that opens every Supernatural finale, “Carry On Wayward Son”, the Wayward Daughters spinoff idea was the result of a grassroots fan effort that started two years ago, soon after Bloodlines, the first proposed Supernatural spinoff, did not go forward. The idea had been embraced by some of the Supernatural actresses who have supported the effort on social media.