The Dark Kingdom (called Negaverse in the original English dub) are the main antagonists in the first arc of the manga and anime, as well as the entirety of the live-action series. Serving under its ruler Queen Beryl, members of the Dark Kingdom attempt to both gather human energy and find the Silver Crystal in order to reawaken Queen Metaria, the evil entity responsible for the destruction of the Silver Millennium.
Black Moon Clan
The Black Moon Clan (called Negamoon Family in the original English dub) are the main antagonists in the Black Moon arc of the manga and in the majority of Sailor Moon R. Members of the Black Moon Clan come from Planet Nemesis, a fictional tenth planet of the Solar System, and have the distinction of having black, upside-down crescents on their foreheads. They are led by Prince Demand, who has been manipulated by the Wiseman so that he and the Black Moon Clan members gather power for him.
The Death Busters (called Heart Snatchers in the original English dub) are the main antagonists in the Infinity arc of the manga and in Sailor Moon S. Led by Professor Tomoe, the Death Busters have as main goal the resurrection of Mistress 9, who in turn would bring the alien creature Pharaoh 90 to Earth to destroy it in an event known as “Silence”.
Dead Moon Circus
The Dead Moon Circus ( called Dark Moon Circus in the original English dub) are the main antagonists in the Dream arc of the manga and in Sailor Moon Super S. Led by Zirconia, members of the Dead Moon Circus are looking for the Golden Crystal, which will allow their Queen Nehelenia to break free of her entrapment within a mirror and take over the Earth.
Shadow Galactica are the main antagonists in the Stars arc of the manga and most of Sailor Stars. Shadow Galactica is an organization of corrupted Sailor Soldiers led by Sailor Galaxia, who devote themselves to stealing Star Seeds, the essence of sentient life, from all in the Milky Way. Their final goal is that of reorganizing the universe in the image that Chaos, the ultimate antagonist of the series, desires.
Hell Tree aliens
The Hell Tree aliens are a minor group of antagonists composed of Ail, Ann and the eponymous Hell Tree, who appear only in the first thirteen episodes of Sailor Moon R. Ail and Ann have wandered around space alone for many years before reaching Earth, where they finally find energy to collect for the Hell Tree so that they can revive it and, in turn, it can give them energy to survive. Unlike other antagonists of the series, their mission was primarily that of survival, not conquest or destruction. In some English adaptations of the anime, their name is changed to “Doom Tree aliens”.
Ail and Ann
Ail and Ann are two humanoid aliens who pose respectively as Seijūrō Ginga (called Alan Granger in the original English dub) and Natsumi Ginga (called Ann Granger in the original English dub), two transfer students that live in the Jūban Odyssey apartments. While trying to blend in with the humans at Usagi’s school, Ail assumes the role of brother to Ann. He develops a crush on Usagi, and constantly tries to win her over, much to the dismay of Ann. He constantly denies these feelings to Ann, knowing her to have fits of jealous rage. On the other hand, Ann develops a crush on Mamoru, and constantly tries to win him over, much to the dismay of Ail and Usagi. Ail and Ann are the only two of their kind, and could be considered as siblings as well as romantic partners since they were both born from the Hell Tree so it would not be lonely on their planet with just the ocean anymore.
The Hell Tree
The Hell Tree (called the Doom Tree in the original English dub) itself is an alien tree that nourishes Ail and Ann, but it becomes weak and requires energy to stay alive. For some time they supply it with human energy to revive but eventually it stops working. In the final episode of the story arc, the aliens try to give Usagi to it as an offering, because Usagi’s energy that the Hell Tree stole caused a sapling to grow on the Tree. The Tree becomes angered and starts to injure those around it, killing Ann in the process. It stops to tell its story to Sailor Moon: the Tree once lived alone on a faraway planet on an island in a vast ocean for countless years until it began to create life (the English dub changed the story to suggest it was once called “The Tree of Life”). It gave energy to its children, but eventually they became greedy and began to fight each other until the planet was destroyed and there were only two small children left, Ail and Ann. It was now weak and needed the energy of love to survive. Sailor Moon uses her power to purify the Tree, and it disappears. Ann is resurrected and when she reunites with Ail, a small sapling appears before them; the Tree has been reborn and they are given a chance to start over, and they leave Earth to live a better life with the Tree.
The Cardians are monsters of the day used by Ail and Ann to obtain energy to revive the Hell Tree. The Cardians are kept in cards until they are summoned by Ail. To summon them, Ail would hold up several cards, and Ann would pick one. The card would then rise into the air and Ail would play a tune on his flute which causes the Cardian to come alive. When a Cardian is destroyed, it changes back into its card form and the picture of the cardian on the card turns black after a few seconds.