Berthier

Berthier appears as a young woman whose white hair hangs in a braid, her blue eyes set beneath the clan's inverted crescent mark. Blue defines her villain wardrobe: a swimsuit, gloves, and boots all rendered in the color.

Once Sailor Moon cleanses her of the clan's corruption, thanks to Koan's pleading, she takes up everyday clothing and loses the small braid once fixed to her forehead. One favorite look is a sleeveless checkered mini-dress in red and black, worn with black heels and a necklace bearing a red diamond, the outfit she sports at the chess event. Another is a crisp white suit jacket over a matching red-and-black checkered top, paired with black trousers and the same heels.

As a Spectre Sister, Berthier is calculating and proud, favoring games of strategy and a chilling composure over open aggression. Beneath the villainy sits a deep vulnerability: when her siblings desert her and Rubeus threatens to cast her out, her confidence collapses into despair. Freed of the clan's influence, she turns warm and playful, cheerfully teasing Petz for being old and grumpy once the reformed sisters open a cosmetics shop together.

Rubeus first sends Berthier to corrupt a Crystal Point in Tokyo, and across two solo assignments she fields the droids Atsugessho and Nipas. After Koan deserts the family, Berthier targets a Crystal Point housed in a chess venue. Ami Mizuno crosses paths with her there and transforms into Sailor Mercury, exposing her secret identity in the clash. Berthier withdraws and enters the building's chess tournament, meeting Ami again in the final round. Ami wins the match, yet Berthier encases the other Guardians in ice and forces a second game under cruel terms, freezing a portion of Ami's body with every captured piece. Tuxedo Mask breaks the enchantment and releases the trapped Guardians, wrecking her scheme.

Calaveras and Petz swoop in to share the glory while she holds the upper hand, but the moment she falters they reveal that Rubeus means to discard her, then leave her behind. Isolated and cornered, Berthier shatters emotionally and tries to freeze herself and the Guardians to death, until Koan talks her back from the brink and Sailor Moon restores her with Moon Crystal Power. She is later seized alongside Koan by Calaveras and Petz, who hope to corrupt them anew, but Rubeus abandons the pair mid-battle and they too are cleansed of evil, making Berthier the second sister to return to the side of good.

Her water techniques, chiefly Dark Water, mark her as the Spectre Sisters' mirror to Sailor Mercury. In the role-playing game Another Story, the villain Apsu forcibly reverts her to her wicked state for a boss battle against the Guardians.