From the writings of Foundation Apex, archivist to Ledaal Visaren of Tuchara:
Each of these devices appears as a polished, mirror-bright black sphere the size of a human eye. Once common in the First Age, they have grown rare indeed, as none remain with the skill to replicate them. Their power to nullify patterned Essence is legendary. Even the spells of the Anathema could be drawn into an Obsidian Eye, to be swallowed by the artifact’s power. They were commonly worn as amulets, offering protection against hostile sorcery.
Most of the Obsidian Eyes now extant in Creation come from three sources:
Ausang Torokanu presented sixteen of these devices to Raikuru the First at the founding of the Shogunate; according to Tula the Elder’s Record of the Nineteen Shoguns, she gathered them from the ruined city of Meru after the Overthrow of the Anathema, though I give more credence to the Diaries of Mahogany Sand, which indicate that Torokanu obtained them through barter, manipulation and outright theft from Dragon-Bloods who had looted them from Meru during the Overthrow. This initial collection increased through the centuries, until over forty Eyes fell into the hands of the Empress after the Contagion.
When the renegade Seventh Legion of the Shogunate destroyed the Pomegranate Brigade shortly after the Contagion, they looted their base of operations in Qasanda. In his Journey to the East, Cathak Rakara provides documentary evidence that, in addition to looting Qasanda of thousands of other priceless relics crafted by the Brigade since the First Age, the Seventh Legion obtained at least thirty Obsidian Eyes. We can safely assume that most, if not all, remain ensconced in Lookshy.
Lastly, once per century, the tribute from the Mountain Folk to the Scarlet Throne contains a single Obsidian Eye. Whether these are relics of the First Age or new creations, no one can be certain. It is my belief, however, that the Mountain Folk are incapable of such craftsmanship; certainly, none of their other known works can match the subtlety of the Eyes. It is most likely that this is a matter of deception: they provide these Eyes to suggest that their powers of artifice exceed their true capabilities.