Luna

Luna was a talking cat and advisor to Usagi Tsukino. It was she who first detected Usagi's power, but at the time did not realise that she was the Moon Princess. Luna and her partner Artemis were advisors to Queen Serenity in the Silver Millennium, and when the kingdom was ruined Serenity used the power of her Silver Crystal to send the two cats to Earth's future in order to awaken the Sailor Senshi.

Luna awakened Ami Mizuno, Rei Hino, and Makoto Kino to their identities as Sailor Senshi as well as awakening Usagi as Sailor Moon.

She and Artemis one day married and had a daughter named Diana who became the advisor to Chibiusa. Chibiusa's toy Luna P was also modelled on Luna.

Manga
In the manga, Luna and Artemis were originally from the planet Mau and in times of crisis could take on human form (as could Diana) briefly.

In her human form, she had long black hair with two odango style buns on the side of her head and blue eyes.

Anime
In the anime, Luna only took human form once, in the Sailor Moon S movie, and Mau was never mentioned.

English Dub
Luna's dub voice, while highly recognizable due to Jill Frappier's take on her, was a focal point of some of the dub's controversy due to the fact that the voice made her out to be an "English-nanny"-type character as opposed to her original implied age (in the Materials Collection, Luna's human form is said to appear a year younger than Usagi). She came across as an aloof mentor/guardian old enough to be Serena's mother, rather than an older-sister character like her Japanese counterpart. Her choice of voice in turn caused a fair bit of problems in the dubbing of the Sailor Moon S movie (which corresponds to the manga storyline "Lover of Princess Kaguya"), in which her human form was revealed.

Pretty Guardian Sailor Moon


In the live-action series, Luna was a talking and moving plush cat (not a real one). As a side effect of being bathed in the light of the Silver Crystal, she could become a human girl and transform into Sailor Luna to train and help the Senshi, but she turned back if she sneezed or was shocked. Her powers employed the use of candy, and she wielded a large folding fan at times. Fans viewed her as the replacement of Chibiusa for the sake of keeping Pretty Guardian Sailor Moon a largely one-series story. As a plush cat, Luna was dark blue instead of black, and her eyes were blue.

SeraMyu
Luna appeared in the first two musicals, Sailor Moon - Gaiden Dark Kingdom Fukkatsu Hen and its revision. Although they remained cats in the story, she and Artemis were played by adult actors in cat-like costumes. They were never referenced again in any other Sailor Moon musical continuity. Luna was played by Tomoko Ishimura.

Trivia

 * Luna's name means "moon" in Latin and many languages derived from it.
 * In the Portuguese dub, Luna was male, while Artemis was female.
 * In the Brazilian Portuguese dub, Luna's name was changed to "Lua," which is the Portuguese word for "moon."