Cast
Odette Yustman as Casey Beldon: a young woman who is paranoid after becoming the centerpiece to a series of supernatural and strange events; eye color, hallucinations, dreams, and seeing strange things. Casey later learns she had a twin that died in the womb, this is all happening to her because a dybbuk (a spirit trapped between worlds) sees her as a doorway to return to the mortal world.
Meagan Good as Romy Marshall: Casey's superstitious and loyal best friend. Romy is amongst those targeted by the dybbuk to effectively weaken Casey to make her vulnerable.
Gary Oldman as Rabbi Joseph Sendak: A rabbi who Casey confides in to stop the spirit.
Cam Gigandet as Mark Hardigan: Casey's skeptical but supportive boyfriend. Initially he is doubtful of all the transpiring events, but he later becomes helpful for Casey.
James Remar as Gordon Beldon: Casey's father.
Jane Alexander as Sofi Kozma: A survivor of the Nazi concentration camp Auschwitz, who is revealed to be Janet's biological mother and Casey's grandmother. Following the traumatizing possession and target by the dybbuk in the 1940s, Sofi becomes knowledgeable to avoid the spirit, and becomes a guide for Casey.
Idris Elba as Arthur Wyndham: A Priest who assists in Casey's exorcism.
Carla Gugino as Janet Beldon: Casey's deceased mother, who was clinically depressed and committed suicide when Casey was a young girl. Janet committed suicide after becoming a target by the dybbuk attempting to gain access to the mortal realm, and the mental effects drove her to commit suicide.
Atticus Shaffer as Matty Newton: A neighborhood boy whom Casey babysits and begins exhibiting odd behavior over the course of the film.
Ethan Cutkosky as Barto: Sofi's twin brother who died in Auschwitz during a Nazi experiment on twins. A dybbuk saw him as a chance to get in the mortal realm, and resurrected him to get into the mortal world. To stop it, Sofi killed "Barto" out of intention to defeat the spirit. The dybbuk continued to appear in the form of Barto throughout the film, ultimately having merged with his soul.
Rhys Coiro as Mr. Shields: Casey's college professor.
Michael Sassone as Eli Walker: An old man in the senior citizen's home Sofi lives at.
Rachel Brosnahan as Lisa: A friend of Casey and Mark
C. S. Lee as Dr. Lester Caldwell
