Skyreach Castle

This flying fortress is owned by the Cloud Giant Blagothkus.
The spirit of his deceased wife, Escarlotta, controls the castle.
The Cult of the Dragon were threatening to destroy the spirit of Escarlotta, forcing Blagothkus to aid them in moving the stolen treasure to the Well of Dragons.
Our heroes snuck through the castle, killing several leaders of the Cult including Rezmir and Azbara Jos. The second Red Wizard, Rath Modar, escaped before they could defeat him.
In the caverns beneath the Castle, our heroes defeated the White Dragon, Glazhael the Cloudchaser, removing the presence of the Cult of the Dragon, and gaining an ally in Blagothkus.
Skyreach Castle is primarily carved from ice.