The project was originally conceived as a film reboot of the film series which started with L'Exorciste (1973), until the idea was reworked as a television series sequel instead. This would not materialize up until L'Exorciste : Dévotion (2023).
Though a sequel to the book and first movie, the TV series ignores the movie sequels.
The internet article Thomas looks up says Merrin and Karris died on March 13, the date the original novel began.
The music played at the end of episode one is Tubular Bells, the same music that is played during the original film of The Exorcist in 1973.
Even though Hannah Kasulka plays the youngest member of the Rance family, she is in fact one year older than Brianne Howey, who portrays the elder sister.