Adventures in the Borderlands
Blessed Bolts of Fiend-Slaying
Sacred crossbow bolts, sanctified for the destruction of demons and devils.
Fiends stuck by this bolt must make a DC 17 Constitution saving throw, taking an extra 6d10 piercing damage on a failed save, or half as much extra damage on a successful one.
Once a bolt of slaying deals its extra damage to a creature, it becomes a nonmagical bolt.