Aquarius

Aquarius, "The Water Bearer", is a Celestial Spirit that is one of the 12 Golden Zodiac Keys. Her Key is currently owned by Lucy Heartfilia.

Appearance
Aquarius is a mermaid-like Celestial Spirit. She has a long blue fish-tail, large breasts, and dons a revealing bikini top. She has two gold armlets, and she wears a jewel circlet. She wields an urn which is the basis of her powers. She was designed to have her appearance correspond with her respective zodiac sign whereby "Aquarius" is depicted as a merman or mermaid carrying a vessel from which is pouring a stream of water, as reflected by the urn and Water Magic Aquarius employs in the Fairy Tail series.

Personality
Aquarius is a very moody and ill-tempered woman who often threatens to kill her owner, Lucy. One of the most important distinctions between Aquarius and the other Celestial Spirits is that while the other spirits serve Lucy obediently, Aquarius is irritated by her. Whenever she is summoned, depending on her mood she will either attack the opponent, Lucy, or both. The risk of summoning her is great because Lucy has said several times she is her most powerful Celestial Spirit. Despite this, Aquarius does care for Lucy's well-being. She is very kind and loving towards her boyfriend, Scorpio, to which she shows a completely different side of herself. She also goes as far as to threaten Lucy to keep quiet about her moodiness in front of Scorpio unless she wants to be a "drowned corpse". Whenever Lucy is within her presence, Aquarius has a tendency to make remarks about having a boyfriend, as well as the fact that Lucy doesn't have one. Despite all this, Aquarius has helped Lucy out several times over the course of the series.

History
Aquarius' previous master had been Lucy's mother, Layla Heartfilia. When Layla retired from her work as a Mage because of her health problems, she entrusted Aquarius' Key to another Mage with instructions to present it to Lucy should Lucy decide to become a Mage.

Macao arc
As Natsu Dragneel fights Bora, Lucy summons Aquarius to haul Bora's ship, full of kidnapped girls about to be sold into slavery, towards the harbor. Happy shows a friendly interest in her given that she was a fish, to which she doesn't respond to. After doing her job (and purposely washing Lucy ashore as well), she states her desire to not be bothered for a week as her boyfriend is taking her on a vacation. Before she leaves, she rubs it into Lucy's face that she has a boyfriend whereas her master does not.

Galuna Island arc
Aquarius is called forth once more when Lucy battles Sherry, to deal with Sherry's Doll Play Magic. Sherry notes that Aquarius is a powerful Spirit and and gains control of Aquarius. Aquarius, however, attacks Sherry along with Lucy because she does not like being controlled. Before leaving, Aquarius berates Lucy's personality, claiming that it is the reason the latter hasn't and will never get a boyfriend like she has.

Phantom Lord arc
It is mentioned by Lucy that Aquarius gave her a very painful punishment (spanking) for losing her keys after she was kidnapped by the members of Element 4.

Loke arc
Aquarius is summoned briefly along with all of the rest of Lucy's spirits when they are confronted by the Celestial Spirit King.

Tower of Heaven arc
Aquarius is summoned again when Juvia Lockser is controlled by Vidaldus Taka. Juvia liquefies herself and Lucy takes advantage of the situation to summon the Spirit through Juvia. Aquarius attacks everyone and Juvia and Lucy join hands to use Unison Raid. After defeating Vidaldus with this, Aquarius mouths off at Lucy, saying that the latter should not ever summon her in such a strange place once again, or Aquarius will kill her. She even comments if Lucy will summon her next from inside a toilet bowl. She leaves again, saying not to call her for two weeks, and commenting, as per usual, that Lucy should get a boyfriend.

Oración Seis arc
Lucy summons Aquarius as her strongest Celestial Spirit in her battle against Angel, especially since the battle is taking place at a river. Desperate to defeat Angel, Lucy tells Aquarius that the Spirit is free to do anything, including attacking Lucy as well, so long as Angel is defeated. Aquarius agrees, but is quickly removed from the battle when Angel summons Scorpio, who is revealed to be Aquarius' boyfriend--a fact that Angel was aware of, but Lucy was not. Aquarius threatens Lucy not to say a word about her usual ill-tempered behavior to her boyfriend, or Lucy shall suffer the consequences. The Celestial Spirits then go off on a date, with consent from Angel, much to Lucy's chagrin.

Edolas arc
After Hughes dumps both Natsu and Lucy into a pond after using Hell Coaster, Lucy summons Aquarius to fight Hughes. Aquarius tries to attack him, only to realize she is rendered unable to control the water, for it remains under Hughes' powers. He then sends her attack back at her and Aquarius screams for Lucy to take cover.

Tenrou Island arc
While fighting Freed Justine and Bickslow, Cana Alberona uses The Prayer's Fountain card, which gives Lucy an opportunity to summon Aquarius. She angrily wave-slashes everyone as usual. She doesn't pick on her usual victim, Lucy; instead, she chooses to bicker with Cana, saying all women are her enemies and that just being 'firm and bouncy' doesn't count as 'justice'. Aquarius also gives Cana zero points as a woman. Through this argument, Lucy takes note of how similar Cana and Aquarius are.

Grand Magic Games arc
Aquarius surprises Lucy and her friends when Virgo brings them to the Celestial Spirit World for a welcome back party. During the party, Aquarius talks to Juvia, noting that Juvia was the one who once used Unison Raid with Lucy when they fought Vidaldus. Aquarius then asks her if she has a boyfriend, causing Juvia to blush and say no, causing Aquarius to comment that she would become like Lucy. During the entire party, Aquarius accompanies Juvia and holds hands with her during the group's departure, signaling the start of a good friendship.

Magic and Abilities
Water Magic: Aquarius uses Water Magic as her primary source of combat. She is a powerful Celestial Spirit; even after Loke, supposedly the most powerful among the 12 Zodiacs, became one of Lucy Heartfilia's Celestial Spirits, Lucy still considers Aquarius on the same level as him, or possibly even above.
 * Giant Wave Attack: An attack in which she absorbs water in her urn and hurls it with tremendous force. She can throw a yacht from a few hundred miles out at sea back to shore.

Levitation: Aquarius can float in the air.

Immortality: As a Celestial Spirit, Aquarius cannot die unless she is forced to stay in the Human World somehow.

Equipment
Urn: Aquarius uses this to cast her Water Magic.

Fairies at the Beach
Lucy originally summons Aquarius to punish her teammates who are causing mischief at the beach where she is waiting for the Sorcerer Magazine staff who are supposed to do a photo shoot with her for their latest cover. However, Aquarius only laughs at Lucy and Taurus arrives in her place instead.

Fairy Academy - Yankee-kun and Yankee-chan!
Aquarius appears as the harsh swimming instructor of Fairy Academy who is able to send people flying from her pool. When called by Lucy, she unleashes a great wave of water from a giant hose that flooded the whole campus, in an attempt to get rid of the students from Courage Academy.

Video Games
Aquarius appears as a supporting character for Lucy in DS Games Fairy Tail Gekitou! Madoushi Kessen and Fairy Tail Gekitotsu! Kardia Daiseidou.

Major Battles

 * Natsu Dragneel, Lucy Heartfilia (owner), & Happy vs. Bora
 * Lucy Heartfilia (owner) vs. Sherry Blendi
 * Lucy Heartfilia (owner) & Juvia Lockser vs. Vidaldus Taka
 * Lucy Heartfilia (owner) vs. Angel
 * Natsu Dragneel & Lucy Heartfilia (owner) vs. Hughes & Byro
 * Lucy Heartfilia (owner) & Cana Alberona vs. Freed Justine & Bickslow

Trivia

 * Lucy's quote when summoning her is: "Open the Gate of the Water Bearer! Aquarius!"
 * She was originally only able to be summoned by Lucy on Wednesdays.