Cybertron

Cybertron is the home planet of the Cybertronians (Autobots & Decepticons) and the body of their creator, Primus. Cybertron is a shining metal, technological world; a planet of towering future cities without end and vast metallic plains, spiraling metal mountains and bottomless neon-lit chasms. Battling over control of Cybertron and its resources is the origin of the Great War. The planet resides in the Alpha Centaurai star system.

The Birth of Cybertron
In the beginning of time, there were two deities, named Unicron and Primus both created by the "One" separating in two. Cybertron already existed prior to their creation and became the battle ground for their war. When the Thirteen defeated Unicron, Primus merged with Cybertron's core and shed his physical body in the process. This act linked the life of Primus and the planet. If one died so would the other.

After Primus had merged with the Core, he used the AllSpark to populate the planet creating a large enough population in three days' time. The newborn Cybertronians clashed with one another before the Great Cataclysm occurred destroying much of the primitive civilization.