Siluria IV is a recently urbanized planet. The climate unobtainable on other planets in Siluria system favors the rampant growth of various plants. Jungle formation is common here, putting new life on the planet. A long time ago it orbited closer to the sun, making it harsh and hot like the rest of the planets in the system. But the gravity field of Siluria IV caught a large asteroid, which gradually became known as the Siluria IV Companion, though astronomers still maintain that the orbit is weak and it is still truly an asteroid caught in a lunar orbit.
Unfortunately, this accident also changed the planetary trajectory, moving it further from the sun. Soon the twisted surface started to fill with water; cavernous valleys turned into lakes and oceans, leaving only a few enormous mountains above the water. Today Siluria IV is a flourishing world, inhabited by a colossal number of species, not all of which are carbon-based. Much of the aquatic life of Siluria IV is unlike that found anywhere else in the known galaxy.