Homeworld Gems

The Homeworld Gems, also known as The Homeworld, are the potential true antagonists of the Cartoon Network TV series, ''Steven Universe. ''They are the original group of gems who exploited Earth for unknown reasons, causing the Crystal Gems to split from and oppose them. They were first alluded to in the episode, Serious Steven and mentioned in the episode, Mirror Gem.

History
6,000 years before the events of the series, gems came to Earth and spread their influence to it, creating gem landmarks and monuments. One of these landmarks was the Kindergarten, a "breeding ground" for creating gems. In an unknown amount of time later, it was shut down by Rose Quartz and her followers. 1,000 years later, a war had started between Homeworld and Crystal Gems, resulting in a victory for the latter. The Homeworld Gems then returned to their world and, over the course of 5,000 years, developed advanced technology like gem destabilizers and impoved gem warships for their second attempt to take control of Earth. In the episode "Laser Light Canon", they sent a scout drone called a "Red Eye" to Earth, to detect Earth-resident gems but was promptly destroyed by the Crystal Gems, without reporting any activity.