Queen Beryl was the commander and mastermind behind the Dark Kingdom. Using Queen Metalia's energy, she started a revolution against the Moon Kingdom in the past and tried to conquer Earth in the present.
Nomenclature and Etymology
Queen Beryl is named after the mineral of the same name.
Queen Beryl retains the same appearance as she does in her previous incarnations, but her costume is noticeably more ornate. Beryl wears a purple dress with pink feathered sleeve cuffs on her shoulders with shoulder armor, that is made out of shiny metal, as well as beryl earrings and a black tiara. Her nails are long and red, and she wears a purple shawl between her arms at all times. Her hair is also red that is also long and curly.
Before becoming "Queen", she was shown to be much less sophisticated and wore a simple gray dress instead. Her hair looked the same.
Thousands of years in the past, Beryl was apparently a courtier at Prince Endymion's castle; she states she was always watching over him. She was in love with Endymion, and she suffered greatly when witnessing his escapades with Princess Serenity. Beryl somehow came in contact with the entity known as Queen Metalia, which granted her power to become Queen Beryl and start a revolution against the Moon Kingdom. Since relations between the Earth and Moon Kingdom's were taboo, people on Earth were easily turned against Endymion for choosing to marry Serenity.
Queen Beryl's revolution was successful, and she managed to invade the Moon Castle; however, after Endymion died during this invasion, Princess Serenity's grief unleashed the power of the Silver Crystal and destroyed both the moon and the Earth, sealing Metalia and Beryl underground in the process.
In the present age, Queen Beryl was revived and she decided to change fate from her past life. She built the Dark Kingdom around the pillar containing Queen Metalia and used her power to resurrect Endymion's Shitennou, brainwashing them so they wouldn't remember their past lives. She ordered them to feed Queen Metalia with people's energy and to find the Silver Crystal so that they could fully awake Metalia.
Queen Beryl's rule over the Dark Kingdom was somewhat chaotic because even though she had full control over the Shitennou's lives she let them act freely. While Jadeite and Nephrite tried to please her and prove themselves to her, Zoisite and Kunzite didn't care for her plans. Zoisite was able to remember his past life and devoted himself to looking after his master Endymion, now reincarnated as Mamoru Chiba. Kunzite also remembered some of his past life and blamed both Beryl and Endymion for the destruction of the planet, so he worked for his own agenda.
The Dark Kingdom failed to find the Silver Crystal, but it revealed itself inside Princess Serenity's reincarnation, Usagi. This revelation awakened Metalia, and Beryl then focused on taking Endymion into the Dark Kingdom and getting her revenge on Serenity. To this end, she created a "shadow" of herself, Mio Kuroki, and sent her to Tokyo. Thanks to Beryl's power, Mio Kuroki became Minako Aino's rival idol overnight. She also transferred to Usagi's school and devoted herself to making Usagi miserable while obtaining information on Endymion's whereabouts.
Mio was able to lead Mamoru to Beryl, but Princess Sailor Moon appeared and attacked her. Beryl was easily defeated, but she resorted to threatening the Shitennou's lives to make Mamoru help her get rid of the Princess. She explained her plans to have Endymion become her King, and even though Mamoru refused they agreed that Princess Sailor Moon's appearance could mean the end of the world once more.
Usagi's use of the Silver Crystal revived Metalia to such an extent that Queen Beryl could no longer control her. Beryl was very concerned that Metalia would destroy the world before she could conquer it, and she unsuccessfully tried to drain Metalia's energy. Finally, Endymion decided to seal Queen Metaria inside his body, eventually turning him into the out-of-control entity known as Metalia Endymion. In this state, he seemingly killed Mio.
Sailor Moon managed to kill Metalia Endymion, but the grief caused Princess Sailor Moon to appear again. Queen Beryl, defeated and powerless, confronted her: the princess had once again taken Endymion, and also Metalia, from her. Princess Sailor Moon announced her intention to destroy the world, and the Dark Kingdom began to crumble. Beryl stayed in Queen Metaria's room and refused to leave. Jadeite stayed at her side; Beryl removed her spell from him so that he could escape, but he still thought of Beryl as his Queen. They died together moments before Princess Sailor Moon destroyed the planet once more.
Although Beryl died, part of her lived on as Queen Mio, which four years later unsuccessfully attempted to rebuild the Dark Kingdom thanks to the four Sailor Senshi (minus Mars) who attacked Queen Mio with the Sailor Planet Attack.