The information in this article is from the fan game The Silver Lining and is therefore not canon.
The Royal Hall (aka Royal Nest) is the palace of Lord Azure (unofficial) and Lady Aeriel (unofficial) in the City of the Winged Ones (unofficial).
Behind the scenes[]
The palace in The Silver Lining doesn't match visually with the Palace Nest seen in KQ6. In fact its a completely different architecture. The Palace seen in KQ6 actually visually resembles the rest of the Winged Ones homes seen in TSL. Incidentally in KQ6, most of the Winged Ones lived in simple nests in KQ6 (rather than the marble buildings seen in TSL).
The palace was actually known as the Palace Nest in KQ6, not the Royal Hall, or the Royal Nest.