There are hundreds of vast islands, each of them with crazy terrain. Each island is independent, but do interact with each other. A few are much more closed off from the others, and some are almost dependent on others. Some of them are great and successful, while others are poor and doomed. All in all, every single person in every single island speaks the same language: English. A few people on Welacruz can speak Apyueek.
There are also a very wide range of weird biomes and ecosystems, monsters, unknown mythical creatures, non-discovered microscopic bugs and parasites, viruses, pathogens, and many more different types of amoeba.
The three largest islands and most popular out of them all would be Welacruz, Vasumious Ryes, and Elland.
Of course that doesn't mean that there can't be other islands. There's hundreds of them. But I'll rule out a couple ones for ya: Maelastia, Aillus, Keijear, Bargt, Vaikufe, Errois, Rhuquens, Sondeck, Etforlon, and Torelcen.