Ras Bolon - the first/last island of the Yellow City

Here is a location from my Yoon-Suin campaign.

The only way to reach the Yellow city from the interior of Yoon Suin is by boat, on the God River.  A hundred miles from the sea, all the various branches of the God River unite and the river becomes mighty indeed, well over a mile wide.  But at this point the rich tropical forests of Lamarakh transition into Láhág, the cursed jungle.  The Lamarakhi boatmen know they must sail for 3 days and nights without pause before they finally arrive at the Yellow City - to stop on the shore is to invite attack by the hostile wildlife of the jungle, or worse

There is one but one safe harbor between Lamarakh and the Yellow city - the island of Ras Bolon.  It is a place of smugglers, river pirates, spies and exiles, and hold its own dangers.  

The island is long and narrow, surrounded by a tall brick wall several feet deep, meant to keep out the flood waters.  During the monsoon, slaves operate pumps ceaselessly to remove the excess water.   The narrow streets see little sunlight and the smell of mold permutes the air.  Smuggled and stolen goods are sold here, and rumors and secrets are traded warily.

Visiting slugmen are invited - with great insistence - to visit the palace of the "Mage of Ras Bolon" - Fo Kulo (mage level 9), an exiled slugman.  He knows well that slugmen who leave the Yellow City carry an excess of yellow tea with them, and the easiest way to obtain it is to force other slugmen to give him a part of this excess - 50 day's worth of the life extending substance is the usual take.  Slugmen in the know therefore avoid Ras Bolon, but the wisest go see him anyway - Fo Kulo may be a arrogant criminal, but he can be reasonable and a good source of information and trade.  His control of the local supply of yellow tea make him the effective ruler over other slugmen exiles unwilling to truly move on beyond the Yellow City.  They fear his power and are eager to extend their lives.  His palace is a squat affair, well defended with many hidden rooms.

His chief rival in the city is Chagdun the Brown, Archmage of Ras Bolon, who resides in a tower at the very south of the island, from which he controls the messenger beetle communications between the island and the Yellow City proper.  Chagdun has two fields of study: enchanted waters and the history of the archmages of Yoon suin.  He will gladly pay for information or samples.  He is well served by a capable fakir and a trio of kenku. Chagdun is actually not a proper mage, but a capable swordsman who has an unusual talent for ritual magics (5e terms:  level 11 fighter/champion with magic initiate and ritual magic feats).  He is not interested in challenging Fo Kulo, but enjoys keeping the slugman off-balance and doubting the extent of his powers.

Currently residing in Ras Bolon is the armored priest Apu Lakmash, follower of the Elephant Demon (cleric 9).  He lets every traveler know that that the Cult of the Elephant Demon wishes the prince Hari Rajan, next in line to the throne of Runggara Ban (one of the hundred kingdoms), dead; and that he will pay 50 rubies for the prince's head.  It is known that the prince is in the Yellow City, but so far the Cult does not dare operate within the city proper.  The holyman is accompanied by two bodyguards - an albino eunuch with his mouth stitched shut, said to be a berserker (Barbarian 5); and a swords-woman from the Hundred Kingdom (5e: Veteran).  Would-be thieves after the rubies have been violently killed in public fashion.  Fo Kulo tolerates the priest's presence as he does not challenge his rule and have been staying at an inn owned by Fo Kulo, paying a premium price.  The rumors of the rich bounty have reached the Yellow City, but on one has found the prince yet.