Complex sentence: Before the Elemental Gearbolt incident, the world was home to two races, Audo and Sulunkan, and the Sulunkan, descendants of a fallen magical empire, were oppressed by the Audo.
Split into simpler sentences: Before the Elemental Gearbolt incident, the world was home to two races, Audo and Sulunkan. The Sulunkan, descendants of a fallen magical empire, were oppressed by the Audo.