"A scatter of yellow-lit honey-dens and brightly painted alehouses. To the south-east rises the stone tower of Cavendish Abbey, its ramparts hung with crimson-and-gold banners. There are zailors from all across the Neath hauling cargo, dicing and brawling good-naturedly on the docks. The air carries the sound of zee-shanties sung with more enthusiasm than skill, and the smell of roses edged with brimstone." "I have, I fear, at last determined the cause of our poor Leopold's sad disappearance. You will recall that I sent by the Borneo a very considerable collection of [illegible] ... identified one variety as the sinister exile's rose of the Bosphorus. Sophia had long admired their colour [illegible] ... gardens here about the Government-house [illegible] ... although here they call it 'lion's rose'. Singapura is Lion City in the Sanskrit [illegible] ... There are of course no lions here, though many tigers. I would not mention this except that when I dream of Leopold, as still I often do, it has always seemed to me that there is a great cat present, the colour of sunset, which is also the colour of the roses..."
The Isle of Cats is the foremost smuggling port in all the Zee. Ships from all over come to smuggle the Neath's most dangerous goods. Here, in the rose gardens of the Pirate King Leopold, is the source of the Neath's most dangerous and addictive drug, red honey. The honey is harvested by Parabola bees (in other words, devils).
The island is run by Leopold, the Pirate King. Despite his infamous reputation, Leopold looks more like a lawyer than he does a pirate. This makes sense, as he is the son of Stamford Raffles, the historical founder of modern Singapore. While in our reality he died in an epidemic in 1821, in this Neathy universe Leopold survived into adulthood. Upon finding and eating an Exile's Rose he was transported into Parabola. Here he gained his affiliation with the local tigers, and the bees he uses to harvest honey. He is also addicted to his own product and will reward those who provide him with subjects ripe for honey harvesting. Directly beneath him are his two disciples: Zaira, Lady of the Cages, and Isery, the King's Claw. Zaira manages the Melliferous Sisters (taken from Abbey Rock) who chant and maintain the Rose Garden from which the red honey is harvested. Isery (the archetype of a Person of Mysterious and Indistinct Gender) is a sort of pirate police chief who maintains order among the rowdy pirates and smugglers who spend their time there. Both Isery and Zaira handle the prisoners kept on the island, and are well respected by the populace; they are also allowed personal audience with Leopold, so they're a potential smuggler's key to getting access to the Gaoler's Honey that so many would kill for in London.
The Isle of Cats is based heavily on the famous pirate haven of Tortuga. Tortuga is also known for being the primary pirate haven for much of the Age of Piracy, as it was run and governed by pirate captains. The Isle was also given a Far Eastern flavor in reference to Singapore, as before the British settled in, it was its own pirate haven for pirates operating in Malacca.
Leopold is especially fond of stolen memories of Singapore and Malacca. It would make sense, given that his father was governor of the British holdings in Java.