You may absolve the wicked of their sins at will. This spell only effects neutral or evil aligned humanoids. A willing sinner need only confess their sins. Their alignment is changed to good for 24 hours, and the stain on their mortal soul is wiped clean in the eyes of the gods. After the spell expires, the creature returns to their old alignment.
Absolving the sins from someone causes the absolver to take necrotic damage equal to 1d6+ absolved character's level. This sin is stored in your body as black ichor. You may vomit that necrotic ichor at any time in a 30 ft cone. Any creature within that cone must make a DC 12 WIS save. The target takes take all of the necrotic damage you yourself have taken from the sin, or half as much on a successful one. The victim of this attack hears the confessed sins of the absolved whispered into their mind as the necrotic energy rots their flesh. Purging your body of the sin releases the necrotic damage you've taken.
Every day you go without purging your body of sin, you take and additional 1d6 necrotic damage, which is not added to the damage you deal upon vomiting.
If your health points are reduced to zero before you can purge the necrotic energy, your character dies, and your body turns into ash. You do not make death saves, do not pass go and collect $200, go straight to Hell. Not Hel, not an outer plane, endless torment in the Judeo-Christian Hell. If you die in this state, you cannot be revived with anything less than a wish spell, or planes-walking into the land of fire and brimstone to wretch your friend from the clawed hands of Lucifer himself.