Klaidicardos

Celestial craft forged this greatsword for the hands of a now-fallen planetar warrior. Once Klaidicardos shone like polished gold in its master’s hand, its blade reflecting sunlit skies—now its light is colder, the blade casting the shadows of storm clouds and lightning.
Sentience. Klaidicardos is a sentient lawful good weapon with an Intelligence of 16, a Wisdom of 20, and a Charisma of 18. It has hearing and darkvision out to 120 feet.
The weapon can speak, read, and understand Common and Celestial, and can communicate with its wielder telepathically. Its voice is cold and clear. Personality. Klaidicardos is consumed with guilt and grief at its master’s fall. Its sole purpose is to bring him to an end, and it will attune itself to any non-evil creature that it thinks might be able to accomplish that goal (even if the sword first needs to help that creature grow in power). Klaidicardos is still tied to its former master and has an innate knowledge of his location at all times. Its wielder is immune to Skanafel’s Howl and Consume attacks, and the fiend is vulnerable to damage from the blade.