Luna is Sailor Moon's guardian cat. She is from the plane Mau. Sh was an adviso to Queen Serenity during the Silver Millenium. She was sent to the future along with Artemis and the royal court when the Moon Kingdom was destroyed by Queen Beryl. Her mission was to guide the moon princess if the Dark Kingdom ever returned. Luna discovered that Usagi was Sailor Moon. She gave Sailor Moon her locket and the Senshi there Henshin Pens (Transformation Pens). She trained the senshi to be good soldiers and tried to keep Usagi responsible. Luna fell in love with an astronomer named Oozora Kakeru, who saved her life. Kakeru saw something falling from the sky. He found a strange looking crystal that had landed near his observatory. When he took it home with him, it made him very sick. Luna wished she cold be human so she could help him. Sailor Moon granted her wish and she was transformed into a human for a short time. Kakeru ended his relationship with his girlfriend, Nayotake Himeko, because of Luna. She realized she was meant to be with Artemis, and told Kakeru his real love was Himeko.
Artemis is from Mau. He was also Queen Serenity's advisor. Artemis is the guardian cat of Sailor Venus. He helped Minako remember who she was and trained her to be a senshi. Minako and Artemis fought against evil in England before they moved to Tokyo. Artemis helped Luna when the other senshi were found. Artemis lives with Minako. Artemis was jealous when Luna thought she was in love with Kakeru.
Diana is Chibi Usa's guardian cat from the future. She is the future child of Luna and Artemis. She's from the 30th century. Diana was a Christmas present for Chibi Usa from her parents. Diana came back in time to help Sailor Chibi Moon and arrived by landing on top of Artemis and Luna. When Diana was a kitten, Chibi Usa always carried her around on her head.
