During the fight with the dragonborn commandos the heroes find out that the dragonborn, too, are after the Wand of Koyss. The group, however, dispatches them to dragonborn heaven along with any answers they could have. After looting the bodies the group uses Rupert to open the biometric lock on the head-shaped door at the edge of the waterfall.
Behind it a staircase leads them to an underground corridor submerged in amniotic fluid. Ada comes up with the idea of using the magical glass orbs that lit the staircase as diving helmets. After some initial reluctance, extensive tests and significant hacks to get Benji into one of them, the heroes cross the submerged corridor to find themselves at one of the entrances of an immense cavern. Inside it chambers have been stacked on top of each other in a grid like layout. A large tower stands in the middle and goes above the ceiling and all over the ground piles of metal plates, leather, tubes and other warforged ingredients gather dust. While the group is crossing the complex they get attacked by a horde of purple-eyed warforged. Between Mara-kai’s tactical decisions and Fenna’s spells the group breaks through the swarm of monsters and reaches the base of the tower.
As soon as they cross the door the swarm of warforged quickly disperses. Seconds later a large scorpion tailed industrial automaton jumps out of a nearby structure. The creature turns out to be the brother of the industrial automaton they met in the jungle. He also turns out to be violent. The group eventually defeats him and pardons his life.
The heroes then proceed to climb up the tower. On their way up they find Baldur, the dwarf who freed Ururl, dying from drinking poisoned water inside the cylindrical structure at the core of the tower. Ururl is nowhere to be seen.