The heroes and their gathered allies lay siege to Tar Elebreth after setting the ward stones. The scion of Evendaloth shatters the outer wall and the allied force pours through the breach, meeting a hoard of undead. The heroes cut their way through the enemy force, then use a device to breath the castle doors while their allies keep the majority of the enemy busy.
In the great hall, the heroes confront undead, necromancers, and a true demon summoned from the second fold, a spider-like creature called Sitria the threadcutter. Mutana is occupied keeping the massive demon at bay, but the other heroes find themselves sorely pressed by undead archers lurking in the shadows. Realizing that the necromancers are fueling the demon, the heroes begin working on taking out the archers and necromancers. Eventually the demon is weakened enough to be slain and the last of the necromancers fall, but the group is badly wounded. After taking a moment to recover, they proceed to the throne room.
The heroes confront Tanisi, who is covered in a protective shield. As the battle gets underway, the heroes realize the shield is powered by four orbs arrayed around the room and guarded by cultists. Mutana attempts to keep the bone giants and the wight of Harusha Blackmane busy while the others deal with the orbs. When the first orb shatters in an explosion, they realize the orbs can also be used to deal with the cultists. Eventually Tanisi’s allies are all slain, and with no ability to flee he is slain by the heroes.