Source: The First World, Realm of the Fey, pg(s). 33
Karaphas' architecture is unknown but obviously non-humanoid. The streets and buildings are decaying, lit by magical light and encrusted with molluscs. A few structures hold trapped air bubbles, but only the Memory Palace has magic that replenishes it.
Karaphas has existed for so long on the bottom of the Cerulean Sea that no one can remember whether it was a sunken city from the surface, or one built from the ground up as an underwater settlement.
Ragadahn makes his home in a temple near the city centre, large enough to hold hundreds of creatures at once. No one knows why Ragadahn pays so much attention on Karaphas, but most speculate that he is searching for something. No intelligent creature is allowed to enter Karaphas without his explicit permission, and even asking for it is to risk being eaten. Despite Ragadahn's legendary jealousy, he is willing to make the occasional exception for when it suits his interests. This restriction does not apply to wildlife, and Karaphas boasts a thriving marine ecosystem with a few species found nowhere else.
A wide variety of creatures have flocked to Karaphas to curry favour with Ragadahn. They have established the Sunken Court, a ramshackle 'town' that straddles around one edge of Karaphas, carefully never venturing into the city itself. Ragadahn has little time to pay attention to them, and allows their leader Linrae to rule them as long as they obey him.