Ruul is a small, rocky planet, avoided by travelers. The unbreathable, dusty atmosphere was not able to stop any object coming from space and a cannonade of asteroids after long years changed Ruul into a hot shell.
After one of those hits, the orbit moved further from the sun. In an incredibly hot climate, life on the planet vanished very quickly. Asteroid impact also caused a series of earthquakes, awakening local volcanoes. Tectonic movements and persisting eruptions rocked its surface, bringing up massive mountain chains, and sealed the fate of Ruul as a deadly piece of rock.