Warning: Contains SPOILERS for The Exorcist: Believer!

Summary

• The Exorcist: Believer brings back Ellen Burstyn as Chris MacNeil, who spent the last 10 years studying exorcisms after her daughter's possession.
• Chris MacNeil became a world-famous exorcist specialist, leaving behind her previous life as an actress.
• Chris wrote a successful book about Regan's possession, but it caused a deterioration in their relationship, leading Regan to hate her mother. Regan went into hiding after the events of The Exorcist.

The Exorcist: Believer's ending brings both back in some capacity by the end and includes details about what happened to them after The Exorcist.

Ellen Burstyn's return as Chris MacNeil in The Exorcist: Believer marks the first time that the actress has played the role since the original. While Linda Blair reprised her role as Regan in The Exorcist II: The Heretic, the movie is no longer confirmed to be canon. The Exorcist: Believer is a soft reboot of the franchise that only acts as if the original 1973 movie has happened. That means that any prior revelations about Regan's life after The Exorcist are no longer confirmed to be true. As a result, the horror franchise has room to provide new explanations for what happened to Chris and Regan after The Exorcist.

5 Chris MacNeil Studied Exorcisms For 10 Years

The events of The Exorcist had a major impact on Chris MacNeil and her life. Ellen Burstyn's character was a successful actress during the events of the first movie. However, experiencing her daughter's possession brought a shift in her career and focus. The Exorcist: Believer reveals that Chris spent the next 10 years of her life studying all aspects of exorcisms. This included spending time in different cultures and learning about various religions. She wanted to become an expert on exorcisms and demons in an effort to figure out how they could be prevented or better performed in the future.

While The Exorcist: Believer does not spend too much time on this part of Chris' backstory, where her curiosity comes from is quite clear. She makes mention of the fact that she was not actually in the room to see Regan's exorcism. It appears that the mystery of what really happened in her daughter's bedroom drove her to learn as much as she could. Instead of focusing solely on following the Catholic faith and its practices after meeting Lankester Merrin, Chris decides to expand her horizons and look at all cultures and religions to find similarities, differences, and the best exorcism practices.

4 Chris MacNeil Became A World Famous Exorcist Specialist

All the research Chris did after The Exorcist means that she became a world-famous specialist in exorcisms. The Exorcist: Believer teases her notoriety in this space by showing a clip from an interview that Chris did on TV. It appears that Chris completely left her life as an actress behind in pursuit of her exorcism knowledge. Her notoriety may have been at its highest during the 1980s, but her overall standing and recognition are still intact when The Exorcist: Believer takes place. Father Maddox (E.J. Bonilla) recognizes her immediately when they meet at the mental institution that Angela (Lidya Jewett) is put in.

3 Chris MacNeil Wrote A Book About Regan's Possession

Chris and Regan's life changed after The Exorcist thanks to Chris deciding to write a book about the entire experience. This is a meta-nod to how The Exorcist is based on a book by William Peter Blatty and is part of how Chris applies everything she studied about exorcisms. Chris' book about Regan's possession and exorcism is called A Mother's Explanation: From Possession To Now. The book's release played a role in Chris becoming so famous after The Exorcist. Ellen Burstyn's character confirms that the book was a huge success. This helps explain how she is living in such a nice house all these years later.

2 Chris & Regan's Relationship Deteriorated After The Exorcist

While Chris' book was a huge success, it did not lead to only good things for the MacNeil family. Chris explains in The Exorcist: Believer that Regan hated her as a result of the book's release and success. There is not much time spent on this revelation, so the exact timeframe for how quickly Regan came to hate her mom is unclear. However, her feelings are quite understandable. Chris turned Regan's traumatic exorcism experience into a presumably best-selling book. It would not be surprising if Regan thought her mom only did this as a means to reclaim her fame instead of trying to help other people dealing with possession.

This is why Chris and Regan have not seen each other for decades by the time that The Exorcist: Believer takes place. That changes in the end thanks to Linda Blair's The Exorcist: Believer cameo. While Regan comes to the hospital to comfort her injured mother, it is unlikely that all is forgiven already. After all, Regan did not have any memory of the exorcism when The Exorcist ended, so Chris' book could have been how she learned about the entire experience. The likelihood that Chris played a part in Regan learning about these events and forcing her to relive them in a public manner explains the distance between them.

1 Regan Went Into Hiding After The Exorcist

The rather successful life that Chris goes on to have after The Exorcist is not replicated for Regan based on The Exorcist: Believer. The original movie leaves Regan's story in a rather happy place, as she does not have any memories of the exorcism or possession. The Exorcist: Believer suggests that she does come to learn about the experience somehow, but whether her memories return or that is strictly through Chris' book is unclear. Regardless, the story of Regan's exorcism coming to light with the public eventually led to her going into hiding for an unspecified amount of time.

It is possible that Regan was hiding for the last 30 years before The Exorcist: Believer. If Chris studied exorcisms for 10 years and then wrote her book, the public response would not come for at least 12–15 years most likely. This could mean that Regan went into hiding during the late 1980s as she became an adult. That gives her a rather tragic story in the franchise overall, as potentially Regan's entire adult life has been spent in isolation or obscurity. That means that her appearance in The Exorcist: Believer is a rather big moment of change for Regan's life as she decides to resurface at last.