The Watch Vaults of the Underlands were a one-time solution to guarding Underland breaches from the Orrish in the lands of light. Few of these were made. Located inside the exit points for the breaches, they were super fortified and those who manned them were paid well to essentially be bait.
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Information Sources: Mundane Reference | Associated Phenomenology Only | Specific Lore
The Watch Vaults of the Underlands were a one-time solution to guarding Underland breaches from the Orrish in the lands of light. Few of these were made. Located inside the exit points for the breaches, they were super fortified and those who manned them were paid well to essentially be bait.
Expensive to make, Druids had to be used to find water sources, and engineers build walls and buttresses inside the large exit points for the breaches.
These employed Ducateon of dwarven traps and shifting passages and floors. The buttresses were warded to provide protection against sappers and miners trying to tunnel under.
When they worked, they were able to contain thousands of raiders with only a couple hundred soldiers for weeks at a time. Some even suffered multi-month sieges, creating time for a large defense force to be brought up.
These employed Light traps to bring daylight in. Polished mirrors on swivels channeled and amplified daylight from the outside into entry points to prevent easy overruns through the entry portals to the defenses. Sometimes they had mechanisms to even bounce it into the caverns where the Orrish were.