CharacterThe main character of the series, called Serena in the English anime (nicknamed Bunny in the manga). Usagi is a carefree schoolgirl with an enormous capacity for love, and transforms into the heroine called Sailor Moon. At the beginning of the series she is portrayed as an immature crybaby who hates having to fight evil and wants nothing more than to be a normal girl. As she progresses, however, she embraces the chance to use her power to protect those she cares about. Not too much longer, it's revealed that she is also Princess Serenity of the Moon Kingdom and also the mother of Chibiusa, changed to Rini in the English manga. Because of her mother, Queen Serenity, giving her last bit of life energy to save her, Usagi is later known as Neo-Queen Serenity in the 30th century. As Usagi continues to play the loved heroine, she transforms into more powerful versions known as Super Sailor Moon and Eternal Sailor Moon. It has also been hinted that she may be Cosmo Sailor Moon.
Source from Wikipeida