Priestslayer

Weapon (longsword), legendary (requires attunement by a lawful good creature)

Priestslayer was created to defeat evil priests and is happy to be wielded by any goodly hero on a quest to fight the followers of any evil god.

You gain a +2 bonus to attack and damage rolls when using this weapon.

Sentient. Priestslayer can speak common and dwarven but is not particularly talkative and is rather single-minded in its focus. If it is used to kill a high priest of any evil religion, it learns to trust its wielder and does not complain if used for purposes other than slaying clerics. It knows surprisingly little about Prince Wales, but is quite helpful deciphering the markings, rituals, or symbols of Chaotic deities.

Blinding Strike. If it strikes a cleric with an evil alignment, the sword emits a burst of light from a gem on its pommel that causes blindness. The target only must succeed on a DC 14 Wisdom saving throw or be blinded for 1 hour. This effect recharges on a 5-6 on 1d6.