|Lives:||Witches 5 laboratory (presumably in Tokyo)|
|Occupation:||Member of the Witches 5|
|Associates:||Professor Tomoe, Witches 5|
|First Anime Appearance:||Believe in Love! Ami, a Kind Hearted Senshi|
|First Manga Appearance:||Act 27 Mugen 1 Yokan|
|First PGSM Appearance:||N/A|
|English Name:||Byruit/Julie Bidou (Cloverway dub), Viluy/Yui Bido (manga, Viz dub)|
|Actors:||Yoshino Takamori (anime), Rina Honnizumi (Crystal), Cricket Brown (Viz dub)|
Viluy appeared as a tall young woman with long pale blue hair, and was extremely intelligent and logical. At one point she accused Ami of being too sensitive and emotional, as she only believed in logic and science, and thought that those who believed in emotion were weak. She was killed when Sailor Moon's Rainbow Moon Heartache attack caused her bracelet to malfunction and her nano robots turned on her.
In the manga, Viluy was stated to be Sailor Mercury's counterpart, and was capable of transforming into a Daimon. As Yui Bidou, she was the leader of the science class and was ranked at Level 202. She met her demise at the hands of Sailor Uranus.
- Mosaic Buster
| Yuka Kuwahara as|
Viluy appeared in the musical Mugen Gakuen - Mistress Labyrinth and its revision, and was played by Nao Futatsugi and Yuka Kuwahara. She was apparently known as a scientific researcher in the musicals, as she was instantly recognized by Ami as the famous Yui Bidou.
- Mosaic Buster
- Viluy is named for viluite, a silicate mineral.
- In the French dub she was never given a name, and had two different voice actresses: one for her Viluy form (Agnès Gribe) and a different voice for her Yui Bidou form (Amélie Morin). She was also nameless in the Hungarian dub, which was based on the French dub, though in that dub she only had one voice actress. In the Brazilian dub she also had two different voice actresses.