The Arcadian Ocean is a large body of salt water on the planet Golarion that lies between the continents of Avistan and Garund on its eastern edge, and that of Arcadia to the west. To its south it adjoins the larger Antarkos Ocean near the Horn of Droon, and its waters extend as far north as the nation of Varisia. The ruins of the former continent of Azlant are found both above and below the Arcadian's waters.
The center of what is today the Arcadian Ocean was once the location of the island continent of Azlant, considered by many to have been the, "... first of the great human realms of prehistory." When the people of Azlant rebelled against the aboleths that had fostered their cultural growth, their former masters responded by destroying the continent; the aboleths triggered Earthfall in the year -5293 AR, decimating ancient Azlant and its people. All that remains of this now-legendary civilization are ruined cities and structures found both above and below the Arcadian Ocean's waves.
The Arcadian Ocean separates Arcadia from both Avistan and Garund, and this massive body of water borders significant portions of all three continents' coastlines. The Arcadian merges with the Antarkos Ocean to the south and extends north as far as the nation of Varisia. Its waters mingle with those of several adjacent seas, including the Fever Sea, the Steaming Sea, and the Inner Sea, the latter of which also connects the Arcadian Ocean with the Obari Ocean to the east.
The Arcadian Ocean also borders the Abendego Gulf, a body of water located along Garund's northwestern coast. Most of the Gulf is now dominated by a continuous and stationary hurricane known as the Eye of Abendego.
Ruins of ancient Azlant
A thousand miles off the coast of Avistan lies a labyrinth of shoals, steep cliffs, and islands, remnants of the long-destroyed continent and island nation of Azlant. The extent of these ruins is not limited to dry land, however; the remains of ancient Azlant extend beneath the relatively shallow waters of this area as well. This is an extremely dangerous region of the Arcadian Ocean, and countless ships and explorers have been lost while seeking the secrets of this ancient human empire.
A series of underwater tunnels connect the Arcadian Ocean to the Sightless Sea far below, a vast waterway located within the Darklands, in one of the Vaults of Orv. Water ascends through these tunnels in defiance of gravity, fueled by ancient aboleth magic. The aboleths protect this hidden waterway and use it as a means to travel between Golarion's surface and their stronghold in the Inverted Sea.
The islands and ocean floor near the former continent of Azlant are dotted with ancient ruins that are home to numerous races, including communities of aquatic elves, gillmen, merfolk, and sahuagin. The remnants of an ancient aboleth civilization are said to exist there as well, where waters from the Sightless Sea ascend to the surface of Golarion; aboleths continue to guard this site and its ancient magics to this day.
Artifacts from fallen Azlant can can be both valuable and powerful. Treasure hunters and archeologists alike travel to the ruins of the island nation to search for the forgotten treasures of this ancient civilization. The elves of the Mordant Spire also frequent the waters of fallen Azlant; though they are based out of the nearby Steaming Sea, these elves believe the legacy of ancient Azlant belongs to them. They were the mortal enemies of the lost Alzanti empire, and continue to oppose the aboleths that currently operate in the region. The Mordant Spire elves actively patrol and defend the ruins from intruders.
- James Jacobs et al. (2011). The Inner Sea World Guide, p. 32. Paizo Publishing, LLC. ISBN 978-1-60125-269-2
- Adam Daigle, Patrick Renie, F. Wesley Schneider, and James L. Sutter. (2012). Oceans of Golarion. Raiders of the Fever Sea, p. 58-71. Paizo Publishing, LLC. ISBN 978-1-60125-409-2
- Erik Mona et al. (2008). Campaign Setting, p. 201. Paizo Publishing, LLC. ISBN 978-1-60125-112-1
- James Jacobs et al. (2011). The Inner Sea World Guide, p. 203. Paizo Publishing, LLC. ISBN 978-1-60125-269-2
- James Jacobs. (July 24, 2012). The Eye of Abendego: What Body of Water?, Paizo Messageboards.
- James Jacobs and Greg A. Vaughan. (2008). Into the Darklands, p. 53. Paizo Publishing, LLC. ISBN 978-1-60125-140-4
- James Jacobs et al. (2011). The Inner Sea World Guide, p. 178-181. Paizo Publishing, LLC. ISBN 978-1-60125-269-2