Strangely enough, out of all the people/cats I was able to find, Luna was the most difficult. You'd think she'd be the easiest, considering that her name is practically synonomous with 'moon' (not to mention the ancient term 'lunacy', which originally meant 'temporary insanity caused by the full moon').
The original Luna ws a Roman goddess of the moon (duh), equivalent to the Greek lunar goddess Selene (see Queen Serenity). Her name comes from the Latin luna; literally, 'moon'.
In ancient Rome, a temple was constructed so that her followers could worship her upon the Aventine Hill. Luna is (as so many lunar goddesses are) traditionally associated with moon magick, transformations (cat into human, anyone?), the psychic realm, and the feminine aspect, especially by those of the Wiccan faith. Her sacred metal is silver (to which alchemists gave her name and for which used her symbol, the crescent moon).