Exorcism

Most (but not all) of the Cleric NPCs in my Lamentations of the Flame Princess campaigns have been Christian clergy. Since my campaigns were mostly set in Early Modern Europe, that seemed to be an appropriate decision. Player characters Clerics have been more varied in their religious beliefs, but then, player characters are always exceptional in some way. Just as there were many infamous witch hunts in the 17th century, there were also many documented cases of (apparent) demonic possession. Often these were integral to the matters under investigation in the various witch hunts, of course. The Christian Rite of Exorcism was employed in such cases to expel demons from their unfortunate vessels, and frankly not only was it more historically and theologically correct, it also seemed more useful for Clerics in most circumstances than Turn Undead!

Here is a spell for Clerics in Basic D&D retroclones and derivatives, like Lamentations of the Flame Princess, intended to let them practice the Rite of Exorcism. I offer the spell as open game content if anybody is still game to use the OGL!

Exorcise

Cleric Level 1

Duration: Instantaneous

Range: Touch

This spell can drive a demon out of the victim of a demonic possession, or assist the caster in the interrogation of a demon which has possessed the mortal target of this spell. It cannot be used to banish a demon which has physically manifested outside of the body of a mortal host (for which purpose the spell Dispel Evil is recommended). The caster rolls 1d20 and adds their level, and either their Wisdom or Charisma bonus (whichever is higher). By placing holy relics on the head of the possessed person, the caster may obtain a further bonus of +1 to +3 depending on the holiness of the relics. The demon rolls 1d20 and adds their number of Hit Dice (the Hit Dice of the demon’s physical manifestation, not of their mortal host). If the caster does not call the demon out by name (if, for example, they do not know the demon’s name), then the demon adds +1d6 to their score. The Referee should roll the demon’s roll in secret. The caster must beat the demon’s score to cast the demon out. The degree of success or failure influences what happens next:

• Caster succeeds by 10 or more: The demon is driven out, and can never return to the same host again. If there is another demon present in the host whose presence is unknown to the caster, it will make itself known and reveal its name.
• Caster succeeds by 5 to 9: The demon is driven out, and cannot return to the same host for at least 3d12 days. If there is another demon present in the host whose presence is unknown to the caster, it will make itself known and reveal its name.
• Caster succeeds by 1 to 4: The demon is driven out of the host, and cannot return to the same host for at least 3d12 days.
• Draw: The demon appears to be driven out of the host, but is still present inside. It cannot resume control over the host for at least 3d12 hours, however.
• Caster fails by 1 to 4: The demon remains. If the mortal host is physically restrained, then the caster can ask the demon 1d4 questions, and the demon must answer truthfully to the best of its knowledge. The demon is not compelled to be helpful, however, and if the caster asks ambiguous questions, the demon is free to give ambiguous (though technically truthful) answers. If the demon does not know the answer to a question, the question is lost. If the mortal host is not restrained, then the demon will force the host to attack the caster.
• Caster fails by 5 to 9: The demon remains. If the mortal host is not restrained, then the demon will force the host to attack the caster. If the mortal host is restrained, the demon will attempt to free the host, lending them superhuman strength (+1d10 Strength) for 1d6 rounds to help break free.
• Caster fails by 10 or more: The caster must make a saving throw against Magic. If they fail, then the demon leaves its current host, and takes possession of the caster instead. If they succeed, then the demon attacks and/or attempts to break free, as above.