Crystal Gems
The exact origins of the Crystal Gems are unknown. What is known is that when the Homeworld Gems attempted to invade Earth, Rose Quartz, thinking it was unfair to all the creatures already living on the planet, started a rebellion and formed the group. In "The Return", it is revealed that at one point there were enough Crystal Gems to constitute an army, but all except a few of Rose's closest friends, whom she protected with her shield, died. For about 6,000 years, the remaining Crystal Gems have used their abilities to defend Earth from countless magical threats. However, Rose Quartz, as a great admirer of humanity, gave up her physical form to give birth to a half-human child, Steven Universe. The other Crystal Gems, Garnet, Amethyst, and Pearl, consider Steven an important member of the Crystal Gems, and the three have taken it upon themselves to raise and teach him how to use his powers.
