Shattenzahn's lair

The Marked Ones arrived in Akek and were granted an audience with the empress. A deal was made in which they were allowed to venture into the lair of Shattenzahn to retrieve the Amulet of the 4th Sphere. In return they would use the power of the Eyes of Azavox to unlock a weapon that would allow Akek to defeat Amon.
  The marked Ones entered the lair and retrieved the amulet. Inside they were confronted by demons from Amon and with Lantana and her minions, but they escaped.