Oyst

Oyst rises up out of the sea like something that rises up out of the sea really well. The island is made up of two halves - the highlands, in the center of each piece, and the lowlands surrounding, with a single bridge running between the two. Each highland was originally its own kingdom, but the western kingdom lost its castle to the sea one dark day after the King got a bit too enthusiastic about ordering still deeper dungeons to be built. The King, his personal Architect (and the Architect's dog), the King's whole family and heirs, and everyone else in the castle at the time, perished in the disaster. After several minutes without rule, the East King took control of the Westlands, and since then the kingdoms have been ruled as one. The two kingdoms originally had names of their own, but these names are lost in time. These days they are called "the Twin Kingdoms of Oyst", or simply "the Kingdom", "Oyst", or (usually) "here". The highlands are mostly self-sufficient, but there's little luxury to be had for most people (except the King, of course).

The lowlands ("there") contains, in addition to wraithwings, unspeakable evils (possibly mothingness). The area between the highlands is in eternal darkness, as the highlands shadow the sun. From time to time, people venture into the lowlands, but never return, and whether this is because people are killed (or worse!) or because they find better places to live is heatedly discussed at regular intervals. People believing the latter tend to go to check out for themselves, and never return, which suits the others just fine.