Steven Universe
Diamonds are the ruling class of the Gem Homeworld, served by servant Pearls. There are four known diamonds: Pink Diamond, Blue Diamond, Yellow Diamond and White Diamond. All other Gems are either assigned to a Diamond (apart from Pink Diamond, because she is not present on Homeworld), or unaligned. Unaligned gems are either rebels or corrupted (corruption is the corruption of a Gem's hard light form, forcing the Gem to take on the appearance of a monster).