Heretic
The blasphemous weapon Heretic was created by a cult to steal power from good-aligned gods. The blade hungers to strike down servants of the Upper Planes and weaken the forces of good.
You gain a +3 bonus to attack and damage rolls made with this magic weapon. Heretic has 6 charges for the following properties; the sword regains charges daily at dawn:
Destroy Devotion. Once per turn when you hit a creature with this weapon, you can expend 1 of its charges to attempt to render the target powerless. The target must succeed on a DC 17 Constitution saving throw or have the paralyzed condition until the start of your next turn. Celestials have disadvantage on the save.
Faith Hunter. While holding the sword, you can use an action to expend 1 or more of its charges to cast one of the following spells from it: Detect Evil and Good (1 charge), Fly (2 charges), or True Seeing (3 charges).
Sentience. Heretic is a sentient, chaotic evil weapon with an Intelligence of 17, a Wisdom of 17, and a Charisma of 15. It has hearing and darkvision out to a range of 120 feet.
The weapon can speak, read, and understand Common and Giant, and it can communicate with its wielder telepathically. Its voice is soft and deep but rises in a wild furor when it's aware Celestials or worshipers of good-aligned deities are present. While you are attuned to it, Heretic also understands every language you know.
Personality. Heretic craves the destruction of good-aligned gods and their supporters. The blade is condescending and snobby, especially in the company of priests and other pious folk, at whom it often directs sneering comments. When Heretic identifies its quarry, it erupts in a frenzied need for violence.