|Alignment:||Moon Kingdom, Crystal Tokyo|
|Occupation:||Student, professional violinist, art teacher (anime only)|
|Family:||Haruka Tenou (cousin; English dub only)|
|Associates:||Haruka Tenou, Setsuna Meiou, Hotaru Tomoe|
|Aliases:||Sailor Neptune, Princess Neptune (manga and Crystal only)|
|First Anime Appearance:||A Beautiful Boy? The Secret of Haruka Tenou|
|First Manga Appearance:||Act 27 Mugen 1 Yokan|
|First PGSM Appearance:||N/A|
|English Name:||Michelle Kaioh (anime), Michiru Kaioh (Mixx manga), Michiru Kaiô (Kodansha manga), Michiru Kaiou (Viz dub)|
|Actors:||Masako Katsuki (anime), Sayaka Ohara (Crystal), Barbara Radecki (dub), Lauren Landa (Viz dub)|
Michiru was mature, calm, and quiet, and it was hard to tell just what she was thinking. She had a distinct sense of humor, though, and enjoyed teasing Haruka. According to the Materials Collection, she had a kindness "as great as the sea." She was an athletic swimmer, a gifted artist, and an accomplished violinist; she often performed in concerts, either by herself or jointly, such as when she held a concert with the Three Lights.
She lived the life of the wealthy Tokyo elite and, in the S season/Infinity arc, attended Mugen Academy, a school for genius students. At the time, however, she attended it to infiltrate its operations.
Michiru had no known relatives in either the manga or the anime series, and seemed to only live with Haruka. In the manga, however, she moved in with Haruka and Setsuna Meiou to raise baby Hotaru after she was reborn at the end of the Infinity arc, and the four of them formed an adopted family. In the original English dub, she and Amara (Haruka) were cousins.
Michiru was romantically linked with Haruka Tenou. Although the anime was not explicit about it, there were hints given (especially during the Stars season) that Michiru and Haruka had a physical relationship. In the first English dub, however, Michelle (Michiru) and Amara were changed to "cousins" in order to avoid controversy surrounding homosexuality. Michiru and Haruka's romantic relationship remained intact in the Viz Media dub.
- When Megumi Ogata, Haruka's voice actress, asked Kunihiko Ikuhara how she was supposed to portray Haruka and Michiru's relationship, she was told to act as if they were a married couple.
- Michiru's skill with the violin extended to playing the instrument while simultaneously juggling a lemon.
- Michiru and Haruka seemed to own a helicopter and could pilot it themselves. In the manga, Michiru had her own helicopter named the Kaioumaru (海王丸; Ocean King).
- Michiru seemed to possess some form of psychic ability that extended beyond intuition. She not only awakened as a Sailor Senshi on her own, she could apparently predict a Daimon attack, sensed Queen Nehellenia's presence, and could tell when Queen Nehellenia was using an illusion on her and Sailor Mars. Her talisman, the Deep Aqua Mirror, possibly enhanced or at least helped her with this ability.
- In 1998, Irwin released a line of Senshi of the Outer Solar System dolls well before Sailor Moon S aired in North America. On the boxes of the Sailor Neptune dolls, she was given the civilian name "Nerissa."
- The Manga of Naoko Takeuchi - Sailor Moon - Materials Collection - Translated by Alex Glover
- Q & A Rocking the Boat (an interview with Megumi Ogata)
|Civilian identities of Sailor Senshi|
|Solar System Senshi|
|Usagi Tsukino | Ami Mizuno | Rei Hino | Makoto Kino | Minako Aino | Chibiusa|
|Haruka Tenou | Michiru Kaiou | Setsuna Meiou | Hotaru Tomoe/Miss Dream | Chibi Chibi|
|Luna Tsukino | Shiva Shingetsu Astarte|
|Kou Seiya | Kou Yaten | Kou Taiki | Princess Kakyuu|
|Shadow Galactica Senshi|
|Chuuko Nezu/Chuu Rat | Reiko Aya/Half Bird | Akane Karasuma/Manila Karasu | Nyanko Suzu | Miss Butterfly|
|Senshi in Parallel Sailor Moon|
|Kousagi Tsukino | Ami Jr | Rei Jr | Mako Kino | Mina Aino|