Moon cats

Luna, Artemis, and Diana

Moon Cats is a fan canon term referring to the feline advisors of the Sailor Senshi, Luna and Artemis, and their daughter Diana. Despite their names, these cats actually originated from the planet Mau.

In the manga side story "Parallel Sailor Moon," there was also a nameless cat who appeared to Kousagi and tell her that she was a Sailor Senshi. The cat's origins were never mentioned in the story, however, so she may or may not have been one of the cats from Mau.