McTavish and Porter portray the brutal cult leaders, with Gillies as troubled sect member, Hope.
Notable recent film credits for the actor includeAquaman,The Finest HoursandCreed.
Previously, Steinbichler has been seen on Netflixs British teen dramaZero Chill, BBC TwosVienna Bloodand more.
(L-R) Graham McTavish, Stan Steinbichler, Susie Porter and Honor GilliesIki Ikram/Margo Jellar/Marnya Rothe/Zak Frankleton
His credits as an actor include the Liam Neeson-led action thrillerMemoryand NetflixsZero Chill.
