Artemis, Diana, Luna

DIANA
Diana is the daughter of Artimas and Luna. She came to the series from the future and is Chibi Usa's(Reni's) gaurdian. In the Anime she appears in SuperS. She appeared in volume 5 in manga. Also in manga, Diana, and her whole famliy, gets turned in to humans.
ARTEMIS
Artemis is Minako's Guardian Cat, much the same as Luna is to Usagi. He was alive during the Silver Millenium, and was an advisor to Neo Queen Serenity. When Neo Queen Serenity sent everyone into the future, she gave Artemis and Luna the task of finding all the scouts once they were on earth. While Luna was working in Tokyo, Artemis searched in France. It was there that he found Minako, the first scout. Minako fought evil in France as Sailor V until Luna found all the other scouts. Once that happened, Artemis brought Minako to Tokyo to join all the other scouts to form the Sailor Senshi.
Artemis has always had a crush on Luna, and later on in the series, they finally get together. They soon learn about Diana, their daughter from the future, who would be the Guardian cat of ChibiUsa.
LUNA
Luna was one of the first characters we are introduced to, and remained a major character throughout the entire story.Luna came to the moon as an advisor to Queen Serenity and aide to the Princess. Luna was reincarnated along with Artemis and the people of the moon during the Fall of the Silver Millennium. Luna was sent to the future in the 20th century. It was Luna's mission to reunite the Sailor Senshi Team, and reawaken Princess Serenity. Unknown to Luna, Usagi, WAS that Princess.