Throne of Anguish
A relic connected to the 9 Hells. Might be some sort of conduit to open a massive portal allowing an army to invade the First Work.
Exact location is unknown at this time, though it is known to be in the Valthunes. The Troupe De Le Foret have confirmed that the tieflings working for the Horn of Geryon as well an unknown force of Duergar.