Castle Vengeance (Migdhal Vengryn in Khazalid) is a powerful Dwarfen blockhouse guarding the former grand entry to the Underdeep of Karak Norn for the Dwarf hold of the same name in the Grey Mountains, now a field of bones and rubble.
Built as a great, two-storey fortified gatehouse that reaches almost to the fire-blackened ceiling of Queen Hargin Ironpick Hall, Castle Vengeance has two purposes: it contains and defends the entrances to the Grand Spiral and Grungni's Back, and it serves as a starting point for expeditions into the Underdeep.[1a]
Manned by a detachment of 25 Ironbreakers, the upper storey is both a barracks and fighting platform. Pierced by loops for crossbows and arquebuses, there are also two portals for flame cannons. The upper storey overhangs the ground floor by a few feet, and trap doors in the floor let the Dawi drop buckets of burning coals and boiling oil on attackers.[1a]
At the rear of the first storey, at a crucial support point in the fort's foundation, lies the powder room. It is not a magazine in a traditional sense. The explosives it holds are not meant for weapons. It is itself a weapon. Should Castle Vengeance be about to fall, the Ironbreakers are under oath to light the fuses and turn the powder room into a great bomb, bringing down the castle and destroying the lowest levels of the Grand Spiral and Grungni's Back.[1a]
Two known doors give entrance and exit to the ground floor, each made of iron and heavily reinforced. The Dwarfs use the smaller to send out scouting expeditions. It is manned at all times by Ironbreakers sworn to give their lives to prevent a breach. The larger gate, made of two iron panels and wide enough to allow passage of whole units and vehicles, has never been opened. It waits for the day when the Dwarfs of Karak Norn march out in force to liberate the Underdeep.[1a]
There is a third door, a postern gate concealed by the finest Dwarf stonemasons to look like part of the cavern wall. Known as the Gate of the Already Dead, it is used by Slayers who have come to seek an honorable death. A private staircase winds down from the Temple of Grimnir on the Deep of Renown that only a Slayer may walk. The sole acknowledgement a Slayer receives comes just before they pass through the gate. At the door, they tug on a chain that rings an iron bell in the castle. At its sound, all Dwarfs bow their heads in respect and say a silent prayer that they should never have to ring it themselves.[1a]