The Cube of Arrick
A matte black cubic about a large handspan square.
The Cube of Arrick is, in effect, a “magical safe”.
It’s surfaces are inscribed with various demonic symbols and it tastes faintly of dried blood.
It was produced using an amalgam of Arcane, Divine and Elemental energy of epic proportions, placing its contents out of phase with the rest of reality. This was done in a manner that effectively nullifies attempts to scry it’s physical location.
The cube can only be “unlocked” by bringing it into physical contact with a specific key item – a pendant which was last traced to Wintermere.
The Cube contains a dimensional key. One that opens a portal to a pocket dimension where a fragment of a hugely powerful artifact has been secreted.