Staff of Azeztos

The Staff of Azeztos is one of the few, if not the last, remaining pieces of the Elder God Azeztos the Hungering Darkness. It is regardless one of the only ways the Elder God could hope to enter The Material Plane and as such should be treated with caution. Records indicate it was one of the artifacts that led to the destruction of the Illithid Empire in ancient days and allowed Azeztos to consume roughly 80% of the Mind Flayer Hives within the Underdark.
The staff in the wrong hands could allow the Elder God to physically invade the Material Plane, and conversley in the right hands could allow for the complete destruction of the Elder God. Though how one would do this is unknown. To destroy an item such as this would take power on par with the entirety of the energy of the Divine Spring.