Plague of Nightmares

8th level Corrupt enchantment spell.
Casting time 1 action.
Touch range.
Components V, S.
Duration instantaneous. 
Book of Vile Darkness

The caster can give one subject touched demon-haunted dreams so vivid and frightening that sleep provides no rest and the subject eventually turns to suicide. The caster must have a chunk of flesh from the target and succeed at a melee spell attack when they cast plague of nightmares. If the target fails a CON save, the spell begins to take effect. Thereafter, the caster must chant for 12 hours per week and pay the corruption cost each week to maintain the spell. The subject begins to feel the effect of this spell the next time they sleep, as nightmares of evil gods and demons plague them. These nightmares continue each night, and each night the subject’s maximum CHA modifier is reduced by 1d4. When the subject reaches 0 Charisma, they enter a trance in which they mentally offer their soul to a demon to be devoured. That night the subject dies and is beyond the help of any resurrection spell. The subject gets a new saving throw each day to resist the spell, and one success is enough to end the nightmares and instantly replenish all of the creature’s lost CHA score. If the spell ultimately succeeds, the piece of flesh used as a focus disappears, alerting the caster that the subject is dead.

Corruption Cost: 1d6 STR drain each week

Any spellcaster that prepares spells can learn these spells. Each spell list has an alignment attached to it. If a creature of a different alignment casts one of these powerful spells, their alignment shifts towards the alignment of the spell by one step. Each spell has a corruption cost that is paid when the duration of the spell ends or according to the spell’s description. If the cost is ability damage, it is restored when the caster finishes a long rest. If the cost is ability drain, it does not recover until the creature receives attention from a Greater Restoration spell.