The Exorcist Code 4: Possession

The Exorcist Code #4

by William Massa

Demonic possession is evolving.
Father Callum and android exorcist Michael face technological horrors beyond imagination.

Discover a series readers are calling a blend of THE EXORCIST and EX MACHINA.

The war between Heaven and Hell has entered a new phase. The Necrocist—demonic serial killer of exorcists—has joined forces with the ghost of a visionary madman obsessed with transcending human biology. Their the perfect vessel for a demon, a nightmarish fusion of flesh and technology.

As faith fractures and technology spreads into every corner of human life, possession is no longer an invasion. It is an upgrade.

Perfect for fans of The Pope’s Exorcist, Sinister, and The Conjuring. A must-read for readers of occult thrillers, exorcism fiction, supernatural horror suspense and science fiction horror.

Genres: Horror

134 pages, Kindle Edition

Published June 30, 2026

Reviews

[Kimberly · Rating 3 out of 5]

I really enjoyed this entire series of THE EXORCIST CODE, by William Massa. That being said, this fourth, and possibly final, installment was my least favorite in terms of plot and ending. It felt more "rushed" than the previous three, and the ending itself just left me underwhelmed. It was fast Paced, but perhaps "too" fast, as any further character development or deepening of the plot were nonexistent. Having read all of the preceding books, I just expected something more in this one.

Still, I recommend this entire series if you're looking for a unique possession theme.