Zion was one of the main planets in the Yathanus system. It was also home to many of the early Bogan species. It had a very small population because it was home to many dangerous beasts like Arn Arn's and Terentateks. Its main city, Hes Tar'k Narn, was home to almost all of the three million people that lived on the planets surface. The city was well defended because it had defence networks that were rigorously maintained by the populace on the planet that was established during the Cruentusian War.
During the Cruentusian War, Zion was attacked by various Military groups, and Hes Tar'k Narn came under heavy attack. Zion maintained its independence until the Cruentusian War was in full swing, when it fell to various military groups, and was ruled by a military government. During the war,the Zion Alliance captured Zion and reunited the planet to one government.