The Dark Kingdom (ダークキングダム, Dāku Kingudamu?) is an organization of antagonists in the Sailor Moon metaseries. They are the primary villains of the first story arc in every version of the series, and are responsible for the destruction of the ancient Moon Kingdom.
This kingdom came into being in the 20th century when the servants of those who had served the evil Queen Metaria millennia before (in the battle against the civilization on the Moon) were reawakened. Queen Beryl and her four Shitennou lead this group, attempting to gather human energy with which to reawaken Metaria.
Creatures called youma (meaning "monster") serve as monsters of the day in the anime. They are summoned by the Shitennou in order to drain energy, hunt the Princess, distract the Sailor Senshi, or perform various other tasks.
DiC's English dub of Sailor Moon calls them the Negaverse, a portmanteau of negative and universe. The term is applied to all enemies in the English dubs of the first two Sailor Moon series, implying that they are all loyal to Beryl or her cause. In the original Japanese anime, the Dark Kingdom is separate from the origins of any other set of antagonists, and is the extra-dimensional location of the evil Queen Beryl and her minions. In the English dub of the Sailor Moon R movie, references are made to Kisenian Blossom sowing seeds of "negativity." Later, when Cloverway took over dubbing, references were made at first to "old enemies" but this was soon dropped entirely. In the English version, the youma are only referred to as "Negamonsters" by the Sailor Scouts (and Tuxedo Mask).