The Pearl Fortress
The Pearl Fortress is an island in The Pincers region of the Wushanko Isles. It is where the Death Lotus assassins have their headquarters and main stronghold. It is also the home of Suzaku the Vermillion Bird, one of the legendary creature of the east, who lives on a mountain overlooking the fortress.
The island unlocks on the map but remains hidden until you reach the Pincers and have completed the story voyage "The Death Lotus".