Weapon: Light's Wrath
Obsessed with cleansing undead from the world of Azeroth, the fanatical Scarlet Crusade tried to create a second Ashbringer in the form of a staff. However, a dreadlord who had infiltrated the order intervened, interrupting their efforts and triggering a violent magical explosion. The damaged staff’s power proved nearly uncontrollable. After several wielders tried and failed to use the staff safely, the elite magi of the Kirin Tor hid it away lest it unleash further deadly calamities.
Weapon: Tuure, Beacon of the Naaru
As beings of Holy Light, the benevolent naaru rescued the draenei from their homeworld after most of its people were transformed into demonic recruits for the Burning Legion. Demons nearly overwhelmed the fleeing draenei, but the naaru protected the refugees with this beacon crystal. Tuure channels the Light's essence into healing radiance, regenerating horrific wounds and bringing people back from the brink of death. Ultimately the crystal was lost to Legion forces on an invaded world. It hasn't been seen since.
Weapon: Xal'atath, Blade of the Black Empire
This terrifying dagger was made from the claw of an Old God eons ago, and dark priests used it for ritual sacrifices during the height of the Black Empire. After the fall of the Old Gods, Xal'atath was hidden away by cults. It has surfaced from time to time over the course of history, inevitably associated with some horrific ritual or disaster. The blade has a will of its own: it uses powerful Void energies and mind magics to warp everything around it for some nefarious purpose.