Sondeck is actually very large, but very few of it is habitable by people. They have a monarchy sort of government, though there are no nobles or peasents, you are either royalty or not. The nonroyals are allowed to vote on new laws, but only royals are allowed to create them. King Noah and Queen Christine currently rule, with their only child being their daughter, Felicita.
Sondeck is covered in volcanoes and rocks. The people mine minerals out of the rock, and sell them to other islands. The volcanoes are still active, and can erupt at any given time. There are no trees, but there are a few dry bushes and plants near the habitable part of Sondeck. Much of the island is not possible to travel to, so only about 1/3 of it has been seen by human eyes.
So far, no characters have been known to be from Sondeck. The population is around 145. Many of the people living there have relatives or houses on different islands, so they can go to them in case a major eruption occurs. The people themselves are very cautious, and are almost always prepared in case there is an eruption and they have to evacuate quickly. Many are miners, but there are a few who are scientists and observe the volcanoes.