Rapier of the Holy Assassin (5e Equipment)
From D&D Wiki
Weapon (Rapier), Very Rare
Rapier of the Holy Assassin
This Rapier was forged by monks assisting a devoted hunter of undead horrors. A Rogue Assassin had lost all to a vampire and had devoted the remainder of their life to hunting the vile creatures. The Rapier grants +2 to attack and damage rolls with an additional 2d6 Radiant damage which becomes 4d6 against any undead creature. Can be used as a spell focus. The blade dimly glows when undead creatures are within 60'of the blade.
The devotion that this blade as made with and that of the wielder at the time of death has imbued the sword with a Holy essence. Any Evil aligned or undead being that tries to wield this sword takes 1d4 radiant damage per turn plus is at disadvantage on all attacks and saves.