Coronaea

The central Triton kingdom, the city of Coronaea is grown from, rather than built into, a great reef in the Coronal Ocean, from which its warriors watch over the Sahuagin deeps.
The city of Coronaea is built upon a volcanic ridge off the west coast of Yethera. The coral reef which has colonised this ridge has been grown and sculpted into dwellings, towers and palaces, both above and below the water.
Above the surface, the overcity clings to the black stone, its walls a resplendent mix of blues, golds and rosy pinks. At the waters edge, docks and warehouses of magnificently carved driftwood line the ragged, hull-tearing shores. On the west side of the ridge, the ocean docks receive shipping from Caino and Suto, while on the east side the little docks see smaller vessels go to and fro from Azeranzerai and other parts of Yethera.
The spires of the Coronal Temple rise high above all else, even the majestic sprawl of the Grand Palace, and also sink into the basalt, emerging to fill a natural break in the ridge at the centre of the undercity. The palace and the temple are linked by the broad, two-mile-long thoroughfare of the Royal Way. The rich manors of the noble quarter lie behind the palace, while the rambling streets behind the temple, known as the Shambles, are where the common folk of Coronaea are most likely to live. East and west of the Way, the Bazaar sprawls down to the docks, home of shops, stalls, guildhalls and merchants' dwellings.
The ridge drops off sharply on both sides, allowing large ships to approach either dock. The undercity sprawls vertically across the plunging cliffs, the lights of coral-grown houses, ranging from cottages to mansions, visible through the clear waters surrounding the city. The undercity is home to the merfolk and sahuagin of the city, as well as the military district - comprised of the city garrison barracks and the Trinium, the headquarters of the kingdom's military command - while the overcity is favoured by sea elves and tritons.
As well as the Coronal Ocean, Coronaea claims control of the Straits of Muna via its military forces, wide-ranging patrols and a number of satellite citadels.