Sailor Moon is a character from the series of the same name. Sailor Moon is the princess of the Moon Kingdom who is sworn to protect the Earth along with the Sailor Scouts. Her secret identity is Usagi (Serena in the English version).
In M.U.G.E.N, Sailor Moon has been created by various creators.
Sailor Moon is a fairly powerful character with a multitude of melee attacks, and other abilities such as her tiara throw and an attack that damages her and anyone nearby that surrounds her in a beam of light. Although she is a little clumsy to use overall due to some of her melee attacks having a bit of a startup time and a short delay after her special attacks, she gains power gradually over time, and her supers are all very powerful and versatile.
When fighting against her, the player should do everything necessary to keep her from performing a super, as these are by far her most dangerous attacks, and each play a scene of Sailor Moon performing the attack in a very well done animation (some of these take a little longer to finish, which may give the player more incentive to finish her quickly.) Her AI is also reasonably competent, and capable of performing an amount of combos up close.
Note that sometimes when she is damaged, Tuxedo Mask will appear to throw damaging roses from a chair. Dealing with this quickly is recommended, as it will quickly get annoying by interrupting your attempts to attack. Hitting him once will make him jump away. This also happens while playing as them, which can be useful for providing extra support when in a tight situation, although his support becomes less effective at longer ranges.
It's worth warning that her file contains slight NSFW material. On rare occasions if she is knocked out: her clothes will become all ripped up revealing her naked. This usually tends to only happen if one is to continue attacking Sailor Moon right after she is completely out of health before the round ends.