"Chilling Adventures of Sabrina" Star Adeline Rudolph Joins "Riverdale" Cast Sparking Crossover Rumors From Greendale to Riverdale! writerrasInstagram Looks like the final Weird Sister is making her way out of Greendale, but she won't be going very far. Riverdalecreator Roberto Aguirre-Sacasa revealed that Adeline Rudolph, who played Agatha throughout the series, is making the big move as the show starts off its time jump. The big announcement also comes during the star's birthday. "Happiest of birthdays to the lovely and brilliant @adelinerudo! She was glorious as Agatha in #CAOS, and I’m so, so happy she’s joining our #Riverdale family post-time-jump as Minerva Marble!! ����������"