William Peter Blatty’s original Exorcist novel heavily implied that Fr. Karras regained his faith and attained his redemption; and that he, Christ-like, sacrificed his life for the possessed child, Regan MacNeil. A beautiful parable. However, Blatty violated this principle in the film, Exorcist III.
Originally written without demonic possession and without an exorcism, Blatty’s original Exorcist III screenplay – based on his novel, Legion – was deemed incomplete by Morgan Creek Studios, which told Blatty to rewrite the story to include an exorcist and an exorcism.
Shortly after this, Jason Miller, who played Karras in the original Blatty-Friedkin film, became available for the project. Blatty hit on the idea of Miller returning, again in the role of Karras. Blatty achieved this through the idea of having the vengeful demon capture Karras’ soul “on its way to Heaven”, and then stuffing it back into Karras’ body along with the soul of James Vennamun, the Gemini Killer. In this new scenario, an exorcism was required, 1) to put a stop Vennamun’s killing spree and 2) to save Karras from the demon’s grip. This was Blatty’s solution to the studio’s demands.
In one way it’s a poor solution because Karras belonged in, and deserved to go to, Heaven. Taking seriously the premise that the demon prevented Karras’ immediate Heavenly reward falsifies the original premise that Karras went straight to his reward. Blatty went on record very early after the release of The Exorcist that “I don’t want people to think that the Devil won” … but in a sense that’s exactly Exorcist III’s scenario: Karras did initially defeat the demon by taking it out of Regan’s body, but then the demon thwarted Karras’ victory by nabbing his spirit and encasing it in his body, which together the demon and the Gemini Killer gradually resuscitate/heal over a twelve-year period. So Exorcist III is a cheat of the original story.
But in another way, Exorcist III “ups the ante” because instead of just the Gemini Killer inhabiting Karras’ resuscitated corpse (as in the novel Legion), Karras himself is now the endangered soul who must be saved. So we now have the Gemini Killer to hate, but we also – again, for a second time, in a second film – have Damien Karras to cheer for, as the story becomes a tale of the efforts of Detective Wiliam Kinderman and Fr. Paul Morning to solve both problems. Additionally, it was a great asset of the film to have a return of Miller himself as Karras, for even the briefest time. But of course, in a just world ruled by a just God, Blatty’s original destiny for Karras as Heaven-bound is the only morally acceptable solution.
Moreover, all along, it helps to understand the fact that Karras didn’t “get possessed”. Unlike Regan (and assumptively most other possession victims), Karras wasn’t the demon’s passive victim. Rather, he deliberately challenged the demon to a personal fight – which Karras did win, despite Exorcist III’s flawed screenplay. Certainly, in a just universe, Karras would not be punished by capture by the demon or by being taken to Hell, but rewarded. Some say he would go to Hell because he committed suicide, but of course that’s a phenomenally misinformed notion. Clearly, Karras gave his life for Regan, much as a soldier might throw him/herself on a grenade to save the lives of comrades. In a just universe, Hell is simply not designed to hold such noble souls. Come to think of it, in a just universe, Hell probably should not exist in the first place.