Aqua is one of the main protagonists of Kingdom Hearts Birth by Sleep. From the view of the story, it is revealed she is one of the Keyblade Wielders before Sora. Like Terra and Ventus, it is her dream to become a Keyblade master, a dream she is the only of the three to accomplish.
While her name means "Water" in Latin, Kairi's name in Japanese means "Sea". The only connection between the two is that Aqua met Kairi in Radiant Garden in Kingdom Hearts Birth by Sleep and put a protective spell on her necklace, which later brought Kairi to Destiny Islands. Kairi, by accidentally touching Aqua's Keyblade during this time, also inherited the Keyblade from Aqua.The official Japanese website refers to Aqua as the "Dancing Waters Forming Bonds" (絆繋ぐ舞水 Kizuna Tsunagu Busui?).
Kingdom Hearts Birth by Sleep
The only one of Master Eraqus's pupils to have been recognized as a true Keyblade Master. A healthy rivalry and close friendship bind her and her training mates Terra and Ven together.
The only one of Master Eraqus's pupils to have been recognized as a true Keyblade Master. Her orders: to bring the Unversed situation under control, and to keep an eye on Terra.
She is very concerned about Terra, as well as Ventus, who ran away from home to find him.
Kingdom Hearts Birth by Sleep
After Terra and Ventus, Aqua was the last apprentice to be sent by Master Eraqus to seek out Master Xehanort and his cohort Vanitas who had previously disappeared. Aqua is known to be a level-minded person, but often worries about her friends. She takes the Master Qualification Exam along with Terra, and becomes a Keyblade Master. Aqua, Ven, and Terra come across many Disney characters along the way and fight of hordes of Unversed. Aqua later ends up at Radiant Garden with Mickey Mouse and meets the Princess of Heart, Kairi, who touched Aqua's Keyblade in fright, unintentionally performing a Keyblade Inheritance Ceremony. They protect her from a group of Unversed and in return Kairi gives Aqua flowers, which becomes the Keyblade, Destiny Place. She also places a protective charm on Kairi to help her in the future. Aqua believes that their meeting may not have been a coincidence.
At one point Aqua and Terra come to Destiny Islands and meet two young boys by the name of Sora and Riku. Aqua sees the strong bond between the two friends and advises Sora to help Riku if he ever falls into darkness. Aqua later encounters an unconscious Mickey drifting in space and takes him to the Mysterious Tower, where she hears of Eraqus's death from Yen Sid and heads to the Keyblade Graveyard to meet up with Terra and Ven. They are confronted by Master Xehanort and his apprentice, Vanitas and a great battle takes place. After fighting Braig and then Ventus under Vanitas's influence, Aqua loses consciousness and she ends up at Yen Sid's Tower with Ventus, who has lost his heart. After creating Castle Oblivion to keep Ventus's sleeping body safe, Aqua tracks down a possessed Terra to Radiant Garden.
Failing to bring Terra back to his senses, Aqua fights and defeats Xehanort, who would have fallen into darkness if Aqua hadn't saved him by sending her armor and Keyblade with him out of the darkness. Now stuck in the Realm of Darkness, Aqua is attacked by several giant Heartless, but is saved by Terra and Ventus's Keyblades. With renewed trust in her friends, Aqua continues on.
Kingdom Hearts II and Kingdom Hearts II Final Mix
Aqua's armor and Keyblade were briefly seen in Kingdom Hearts II Final Mix. They reside in the Chamber of Repose, a room constructed by the Apprentices under Radiant Garden for an as of yet unknown purpose. Xemnas visits the armor often, calling it "friend" and talking to it for long periods of time. This has piqued the curiosity and suspicion of Xigbar, who often eavesdrops on his conversations, and once shared this story with Zexion, stating that one time he heard "another voice" respond to Xemnas. In The World That Never Was, Sora encounters Xigbar, who mentions "other Keyblade bearers", referring to Terra, Aqua, and Ventus.
Aqua ends up at the Dark Median, where she meets Ansem the Wise, who was cast into the Realm when his machine exploded. He reveals that in the Realm of Light, it has been almost eleven years, and he explains the events that have occurred in Aqua's absence, including the actions of Sora. Knowing that Sora will rescue her and her friends, she utters Sora's name with renewed hope.
Aqua is described by Tetsuya Nomura as being "tricky". A magic-based fighter with agility to boot, she's capable of doing cartwheels while attacking with her Keyblade. While she's more than capable physically, her prowess lies with a more magic-oriented fighting style, being versed in all forms of it. Aqua is second only to Master Xehanort in terms of magic amongst Keyblade Users, displaying superior skill to both Terra and Ven as well as later Keyblade users such as Sora and Riku. She has her own special variations of the Fire, Ice, and Thunder spells, and can cast the Reflect spell indefinitely without tiring, effectively giving Aqua a 360 degree defensive zone. She can also augment her jumping abilities with magic. She is the slowest of the trio, however her slender frame makes her a difficult target. Small petals also appear when she summons her Keyblade. Her known Command Styles are:
Her own exclusive Command Style; it utilizes the power of light to hover her Keyblade in midair, swiftly attacking enemies while enhancing her magic capabilities as well. Activated by filling the Command Gauge with a variety of multiple magic-based commands. The finisher consists of Aqua performing a magical spin attack that can be controlled with the analog stick. This was called "Magic Wish" in the Japanese release.
Aqua's high speed Command Style and exclusive to her; it allows her to attack enemies at high speeds while using after-image illusions and tricky movements to her advantage. Activated by filling the Style Gauge with Thunder and Magnet-based commands. The finisher consists of Aqua circling a certain area before creating an explosion.
Activated by filling the Style Gauge with Fire, Blizzard or Strike commands. In this Command Style, the Keyblade resembles a large, glowing sword. The finisher consists of Terra or Aqua spinning the blade to hit surrounding enemies, and then smashing it into the ground.
A style that gives Aqua a great midair advantage, it allows her to ride her Keyblade around to attack foes from above at high speed. Activated by filling the Style Gauge with evasive, or Zero Gravity-based commands. The finisher consists of Aqua mounting her Keyblade and hitting multiple enemies before heading skyward then crashing back down and finally, spinning on herself causing a small tornado. This was named "Air Rider" in the Japanese release.
Aqua becomes a D-Link for Terra and Ventus, after they received the Wayfinder, Aqua made for the three of them. While in link with Aqua, the player can utilize powerful magic attacks.
Rainbow Shower: Light in seven colors bursts from the Keyblade and chases after enemies. Press ( in Japanese versions) at the right time in the circle to input the command. “An attack with light in seven colors.” “A spiraling light whirlwind, a rainbow attack, again!” This move bears a slight similarity to Sora's Ragnarok technique.
Bubble Blast: A giant bubble appears around Aqua and attacks by releasing smaller bubbles that chase after enemies.Press ( in Japanese versions) to fire bursts of two additional bubbles. It is named "Bubble Blast" in the Japanese version.
Shiny Bloom: Aqua twirls on the spot while shooting many orbs of white light. As it progresses, her spinning becomes more and more elaborate until she is spinning with one of her legs behind her head.It is named "Shiny Bloom" in the Japanese version.
Aqua's exclusive Keychains generally share a water-theme and are primarily focused on magical strength; in fact, her "Brightcrest" is the most magically-powerful Keyblade form in the game. Her Keyblade and its forms are of medium length, between those of Ventus and Terra. Aqua starts off with her personal "Rainfell", but after visiting the Destiny Islands, she obtains a more powerful version of it named "Stormfall". However, after falling into the Realm of Darkness, she sacrifices her Keyblade and Keyblade Armor to save Terra, and is forced to use the Master Keeper, which she had retrieved earlier.
Aqua shows some similarities to Kairi, which she shows by making good luck charms for her friends. She also has a devotion to her friends similar to that of Sora's, for she did everything in her power to protect Ventus from harm and even sacrificed herself to save Terra. Her personality is serious, kind, strong willed, and responsible, as she is the most reliable of the three. She is always worrying about Terra and Ventus, who she treats as brothers. She has been shown to be blushing and embarrassed when Zack asks her to a date, shaking her head and arms in an attempt to compose herself. She seems rather modest, as despite becoming a master she still referred to herself as a trainee. The only time she referred to herself as "Master Aqua" was toward the end, when she fights the possessed Terra.
Aqua looks slightly like Kairi, but older. She has similar blue eyes, but her hair is blue and shorter. She wears a black and blue, high-collared halter top, two pink, intersecting belts over her chest, and black shorts. She wears an odd silver badge similar to badges also worn by Ven and Terra, though Terra's is gold. On Aqua's arms are white bell-sleeves and tan, fingerless gloves. She also wears a small, segmented piece of armor on each of her upper arms. She wears what appear to be black stockings or socks on her legs which reach to about halfway up her thighs, leaving a small area of bare skin on her upper thighs. Aqua also bears two strips of blue cloth that drape over either side of her hips, along with a smaller, white strip of cloth tied around her waist, draped in the same manner. Finally, she wears pointed, armored, silver boots with a sharp "hook" on the outer side of each.
By touching the piece of armor hanging on her arm, Aqua will become full clad in her Keyblade Armor. In Birth by sleep, Aqua's armor is mostly colored in shades of silver, black, grey and blue. Notable additions include a silver breastplate resembling an upside-down crescent moon and a dark-visored helmet. Her helmet, like Ventus and Terra's, bears two prongs on either side, with her silver ones wrapping around the sides and angling diagonally downwards. Her cape is that of a dusty-rose color. In Kingdom Hearts Birth by Sleep, Aqua's armor remains largely unchanged, though she loses her cape and grey becomes a more dominant color than black or blue. She also gains more armor near her upper legs and hips.
During the development for Kingdom Hearts Birth by Sleep, Aqua's outfit was altered, as Tetsuya Nomura considered her exposed back to be too revealing, ultimately resulting in an outfit that is neither too conservative nor too revealing. As well, her eyes and hair were originally darker.
Artwork of Aqua from Kingdom Hearts Birth by Sleep's promotional artwork shows her hair spiking near the back of her head and falling just past her neck, as opposed to the spikes being splayed to the side and the back stopping short of the base of her neck.
While she doesn't appear in the game, in the Kingdom Hearts Re:coded opening Aqua is briefly shown on the Dark Margin during her conversation with Ansem from Blank Points.
* "Would it be alright if.. I tried on the glass slipper?"
*"Do you think maybe...my circle of friends
could become part of yours?"
* "I made us good luck charms."
* "Somewhere out there, there's this tree with star-shaped fruit; and the fruit represents an unbreakable connection. So as long as you and your friends carry good luck charms shaped like it, nothing can ever drive you apart. You will always find your way back to each other. An unbreakable connection!"
* (to Braig) "Go ahead if you want to waste your time. You try to drive us apart with your mind games, it'll never work!"
* "He's not as weak as you think!
* "My name is Master Aqua. Now return my friend’s heart, or pay the price!"