A Celestial Spirit that Lucy received after claiming her key from Duke Everlue.
Virgo is one of the twelve Zodiac Celestial Spirits who possesses great strength and powers that typically involve moving earth. Lucy received Virgo's key after Duke Everlue, the previous owner, was defeated and arrested. After being summoned by Lucy for the first time, she demonstrated that she can change her physical appearance to suit her master's tastes after she changed from a horrendous looking maid (the form she used when she served under Duke Everlue) to an attractive, young looking girl. She also acts as a tailor who provides Lucy (and even other Fairy Tail members such as Natsu and Wendy) with clothing from the Celestial Spirit World whenever she needs it. Over time, Virgo has developed the the power to summon herself without Lucy having to do it which requires her to use her own magical power. And like other Celestial Spirits, she can only be summoned on the days agreed to between her and Lucy which are Mondays to Saturdays.
Virgo, created by Mashima, was designed to resemble a maid as an obvious play on her title of "The Maiden" and ironically, she enjoys punishment (which may be represented by the chains on her wrists) which adds a comical side to her Zodiac sign.
Virgo can take on different forms depending on her master. When Virgo was first seen she was under the control of Duke Everlue, who had a taste for ugly looking woman so she took on the form of a female ogre nicknamed "Gorilla Maid" by Natsu. It was here that she first showed her powers for tunneling and her enhanced strength. However, during the Lullaby Arc, Lucy gained her key and summoned her, revealing her to now have the form of a cute, young girl. She offered to return to her ogre form if that is what Lucy wanted, but she quickly declined and said she preferred her younger form. She always wears a maid outfit which is an obvious play on her title, "The Maiden." However, at times, she may alter her attire to match the one that Lucy may be wearing. In the S-Class Trial Arc, for example, when Lucy summoned her, she wore a bikini just like her, or in the OVA, Fairy Hills, Virgo had cat ears and a tail since Lucy was dressed in a cat outfit.
She is on good terms with Lucy and is very obedient, although she does have a habit for going overboard with everything and has exhibited a taste for punishment. She also acts very formal and addresses Lucy as "Princess" to express her servility to her. In addition, she has exhibited traits for being something of a tailor, or at least continuously provides Lucy with clothing and other items. In the manga this is first seen in the Oracion Seis arc where she brings both Lucy and Natsu new clothes from the Spirit World. Previously in the series during the Tower of Heaven Arc Cancer had given her new clothes as well, but apparently Virgo worked better for this because when that issue was adapted for the anime it was changed to being her who gave her the clothes. Also during the Edolas Arc Virgo provided Lucy with a new weapon, the Fleuve des Etoiles, a whip from the Spirit World.
Virgo has the ability to tunnel through the earth and has shown signs of super strength. Later it is seen that the two aren't necessarily related and that she doesn't just burrow through the Earth, she can actually manipulate the Earth to some degree, as she is seen creating large a large pit during the Edolas arc that she throws Byro into.
Virgo also has the power to transform into whatever her owner finds most suiting.
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The first anime film adaptation of Hiro Mashima's manga series.
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This is the 2nd OVA/OAD episode in the Fairy Tail franchise.