Ancient Mu Relic
This is a souvenir found in an ancient Mu temple from a tale you like to call:
Forging the Blackwand
It all started when the ancient sorcerer Tarixus spoke to you of a ritual that would give his ghostly form more power over the world of the living. In order to enact this ritual, he needed to create a magical artifact called the Blackwand. The construction of such a device was detailed in a book called the Abyssal Tome, an ancient book you acquired from the Legacy Chain.
Next you tracked down a Scrapyarder leader who was an unwitting descendant of the ancient Mu civilization and gathered some of his blood.
You then invaded a gathering of Freakshow in an attempt to reacquire ancient Mu relics. The Freakshow were unsuccessfully trying to unlock the secrets of the relics when you arrived, and you quickly overcame them.
The final item needed for the Blackwand was the soul essence of a defeated hero. Tarixus sent you to a Longbow base where you took down the hero known as Agent X and stole his soul essence.
Tarixus created a Charm of Making and sent you to a hidden Mu temple deep underneath Potter's Field. When you entered the Temple the Circle of Thorns came calling, hoping to steal the secrets of the temple. Fighting through to the Obelisk of Yendor, you invoked the Charm of Making and created the Blackwand. The energies of the Mu temple were directed to Tarixus in the process. In return for your service, Tarixus allowed you to keep the Blackwand.