Act Four, or The Chambers, is the fourth and final act of the Castle Hammerwatch campaign.
Act Four has three floors: Floor 10, Floor 11, and Floor 12. The act has a much better appearance than the rest of the castle, though it still appears run down. Act Four uses Theme D in the Editor.
Act Four, unlike the first three acts, does not introduce any new enemies. It includes liches, skeletons, and archers. In the boss room, demon eyes and wisps can also be found. Nova towers return as the primary stationary enemy.
- Main article: The Dragon
The boss for The Chambers is The Dragon. He is surrounded by a large amount of wealth, and is difficult to defeat.