The Void's Cosmic Lock

The Void, an entity named for its unending emptiness and eternal hunger, once posed a threat to all of creation as it consumed the essence of all it encountered. Because of this, once the Void was finally captured the Creators all banded together to form an impenetrable and inescapable prison for it. As a precaution, they built an enchanted cosmic lock on the prison, as well as sealing every gateway between realms to protect the others, should the Void ever escape.
The pieces of this lock are made from an incredibly dense and strong metal with complex magics infused into their very particles. The pieces work together, interlocking, rotating, and powering one another in a perpetual motion machine. The chance of a piece breaking couldn't be risked in its creation, thus the individual pieces were enchanted to heal and strengthen one another. While each piece is powerful and emits its own unique energy field, in order for the machine to be strong enough to contain the Void and restrain its powers, every piece must be in place. Knowing that even the most well crafted designs or the strongest enchantments could go haywire, a special piece was created for this device. It was granted a limited form of sentience, meant to observe and learn in its eons of existence, so that it could reliably identify who, that wishes to take administrative control of the lock, is worthy to do so. This piece forms the wheel that must be turned to open or close the entrance of the Void's eternal prison.
Over time, pieces of the cosmic lock were lost, slipping into other realms through tears in the fabric of existence too small for most creatures to pass through. One of such pieces was the wheel or Circlet of Divinity, as the mortals of Torus call it. On the mortal plane, it has served a very different purpose. It has been used as an energy source, to heal and prolong the lifespan of certain materials - including mortal flesh, and to those the Circlet deigns worthy, unleash otherworldly powers.