Raised In Dungeon Volume 9
The Arcaneblade Incident Arc
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In Oxwadeshire, there were four elevators that transported people to the various lower floors. Each elevator made stops on every floor in Oxwade except for the 10th floor, which was designated as a forbidden place. However, the 10th floor wasn't the only floor without an elevator stop. Other floors that the elevators bypassed included the fifth, sixth, and seventh floors.
The fifth floor held the ocean,
The sixth floor housed the principal's room,
and the seventh floor contained...
the inverted mountain of Aarakocra.
As the name suggests, this floor features an inverted mountain with its peak at the bottom and its base at the top. The Aarakocra carved out a cave within this upside-down mountain.