Berthier is the 2nd youngest of the Spectre Sisters to confront the Sailor Guardians.
Nomenclature & Etymology
Berthier is named for the mineral Berthierite. Her Japanese name is Beruche. Beruche is a shortened form of the mineral, Berucheko (the ko part that was removed is the Kanji for "mineral/ore"). Berucheko is the Japanese name for Berthierite.
She is a young woman with blue eyes, white hair in a braid, and the Black Moon symbol on her forehead. She wears a blue swimsuit, blue gloves, and blue boots.
After being purified by Sailor Moon due to being convinced by Koan, she wears casual outfits. She also wore two primary casual outfits; her first outfit is a red and black checkered sleeveless short dress and black high heels. She also accessorizes it with a necklace with a red diamond pendant in the center. She wears this during the chess competition, and her second outfit is like from her first outfit is a white long-sleeved formal suit jacket with a red and black checkered sleeveless undershirt, black slacks, and her black high heels from her first outfit. She no longer has an extra braid on her forehead.
After Koan left the Spectre family, Rubeus sent Berthier to take over a crystal point in a chess building. Ami Mizuno encountered Berthier and transformed into Sailor Mercury to fight her, revealing her true identity to her. Berthier retreated from the battle and entered the chess tournament, where she faced Ami in the finals. Although Ami won, Berthier trapped the other Sailor Guardians in a ball of ice and started another game of chess with Ami, except this one was with her own rules - whenever Ami lost a piece, a part of her body would freeze. The spell was shattered by Tuxedo Mask, who freed all the Sailor Guardians, and Berthier's plan was foiled. Calaveras and Petz had appeared to reclaim some of the credit when Berthier's had the advantage but explained that Rubeus was going to kick her out for her failure and abandoned her. Berthier, alone and outnumbered, broke down and attempted to freeze herself and the entire Sailor Guardians to death. Koan convinced her to stop and change her evil ways, so Sailor Moon used Moon Crystal Power on her.
Berthier was later captured along with Koan by Calaveras and Petz in an attempt to turn them evil again, but in the battle that followed, Rubeus ditched Calaveras and Petz, and they were also healed of their evil. Berthier is the second of the Spectre Sisters to turn good, and she happily mocks Petz for being old and cranky when she and her sisters open a cosmetic shop together.
- Berthier is the Spectre Sister counterpart of Sailor Mercury, as they both use water-based attacks.
- Berthier is forcibly changed back to her evil self by Apsu and is a boss fight in Sailor Moon RPG Another Story. However, she, like her sisters, seem to have control of their minds, as they tell the Sailor Senshi they don't want to fight them, but their bodies are forced to fight the Sailor Guardians; in this battle, the Sailor Senshi are forced to kill them. It is unknown if they were revived at the end.
- Berthier is named after berthierite, an iron sulfide.
- She is called "Bertie" in the original English dub.
- In the original Japanese version, she is the 3rd oldest of her sisters. In the DiC English Dub, Bertie is the youngest of her sisters.