Aqua is one of the three playable characters of Kingdom Hearts: Birth by Sleep and the initial primary character of The Interference: Across Time and Space. She is a Keyblade Master from over a decade in the past, and an ex-apprentice of Master Eraqus, who fought against Master Xehanort.
For an unknown period of time, Aqua was trained alongside fellow student Terra underneath the Keyblade Master Eraqus at the Land of Departure training grounds.
One day, Eraqus' old acquaintance Master Xehanort brought a boy named Ventus into Eraqus' care. The questions that Aqua and Terra asked the boy about his past caused him to overload and faint; it turned out that Ventus suffered from amnesia and was ill as a result. Aqua waited for Ventus to wake up, eventually alerting Eraqus when he did so. Since that day, she, Terra and Ventus all trained together, bonding as close friends and acting almost as siblings to one another.
Four years passed and Aqua and Terra entered their Mark of Mastery exam together, over which Master Xehanort also presided as a guest of Eraqus; Aqua won the title and began instruction in the rights and duties of a Keyblade Master. However, they were interrupted by news of a new threat: that of the Unversed. Terra and Aqua were both dispatched to defeat the Unversed and track down Master Xehanort, who went missing after the exam. Aqua was also instructed to watch over Terra. Upon attempting to leave, she witnessed Ventus also escaping the world on his own Keyblade Glider, and Eraqus commanded her to retrieve Ventus at once.
During her travels, Aqua briefly met with both Terra and Ventus again, failing to rein Ventus in and becoming more and more distrusting of Terra. Aqua also engaged in battles with a masked boy by the name of Vanitas. At one point, she rescued a small girl from the Unversed with the aid of King Mickey. At another, she travelled to Destiny Islands to meet two boys and, noticing one was gifted with the ability to use the Keyblade, asked the other to keep his friend afloat in the future. Meeting Mickey again soon after in the Lanes Between, she took him back to Yen Sid's tower, and learned of the death of Eraqus.
She headed to the Keyblade Graveyard where Mickey had been previously, and met with Terra and Ventus once more. Terra had felled Eraqus and Ventus was apparently intended to become part of a '𝛘-blade', news that shocked her. They were then confronted by Master Xehanort and Vanitas. A battle was fought, and Ventus' body was frozen and tossed aside. Upon trying to reach it, Aqua was distracted by Braig, who caused enough of a diversion for Vanitas to merge with Ventus. Aqua's battle with the possessed Ventus broke the malformed 𝛘-blade and flung both her and Ventus into space, unconscious.
Mickey recovered their bodies from space and brought them back to Yen Sid's tower. When she recovered, she learned that her friend's heart had been lost.
The Interference: Across Time and SpaceEdit
With Ventus in tow, Aqua takes her fallen friend back to the Land of Departure. Remembering a technique taught to her by Eraqus upon her qualification as Master, she uses the Master Keeper on the world's Keyhole, which transforms the world into Castle Oblivion. However, as she does so, a thief steals Ventus's armour and Keyblade right off his body and makes a break for it.
Aqua chases the stranger out of the castle, whereupon she challenges him; he brushes off her challenge and, after a flash of light (from an alchemic transmutation), reveals himself to be donning Ventus' armour, as well as his face. He introduces himself as Kronos and falsely reassures Aqua that he is only there to carry out a revenge scheme several years in the future, before casting a red portal. Before Aqua can follow him, Kronos warns that her leaving her time period will cause a time paradox if she does not return.
After he disappears, another, green portal opens next to her, and out steps another Aqua, one from the end of her journey. This future Aqua reassures the Aqua of the past, informing her that she has created a stable time loop by returning, and requesting that Aqua track down a man called Alexander.
Aqua jumps through the red portal before it closes, which leads her to the world of Guardia. There she encounters Kronos, along with his cohorts Hyperion and Themis, who are wearing the other armours. To her surprise, Lucca, then Lea and Goofy, all converge upon the same point, causing the trio to flee to Amestris, and leaving the others to try to understand what is happening.
After introductions and explanations are shared, Aqua asks several questions about this Alexander, doubting their talk of the worlds being fictional and there being a real external world. The others argue that Alex does enough genuine good for them to want to vouch for his stories which, while still suspicious to Aqua, is enough for her to accept and move on.
The group cannot visit Amestris, which is blocked off by mysterious means; their only other option is to travel directly to Haven City where Alex was last seen. Their ship draws the attention of Even, who after confronting them with a video call sends a Heartless with a bomb onto their ship. The ship explodes above Haven's atmosphere, and Lea activates the teleporter before impact. Aqua falls into the Bazaar.
Returning to her original time, Aqua headed to Radiant Garden to find Terra, who had been possessed by Master Xehanort, about to destroy the world. They battled, and during the fight Xehanort stabbed himself with his Keyblade in order to destroy Terra, summoning a portal to the Realm of Darkness. Desperately, Aqua dove into the portal and flung Terra back out, along with her armour and Rainfell, sacrificing herself in his place.
Now in the realm of Darkness, Aqua considered letting the Heartless destroy her; in response, Terra and Ventus' Keyblades come to her aid, literally flying through her and restoring her will to survive. She began to make her way through the Realm of Darkness, eventually coming across the Castle of Dreams, a world she had visited during her quest which had in the meantime fallen to darkness.
Aqua is a controlled and confident young woman in her late teens to early twenties, but often comes off as much older due to her maturity. As a Keyblade Master, she is confident in her own abilities, though not boastful, and very disciplined, remaining calm in situations most others would find stressful; however, it is possible to crack her resolve when facing her with a deeply personal hit against one of her close friends, and it is one of two ways to throw her entirely off-guard.
She is quite skeptical, particularly of the Interference phenomenon (which in the text is described as a perfectly natural reaction). She is also very closely aligned with the forces of light, due to her history, and shows a distrust of darkness.
Aqua is a thin woman of average height with pale skin, cropped blue hair and blue eyes. She dons a dark blue halter top with reinforced black panels on her chest (crossed by a pair of pink straps connected by a silver badge) and a black underbust corset. Around her waist is a white sash knotted at either side, and descending from her hip to her ankle underneath the knots are a pair of long blue strips of fabric. She wears black shorts, long black stockings, and large armoured shoes with a hook on the outer side of each cuff. She also wears long white detached sleeves with small armour plats on the side, which activate her Keyblade Armour.
When donning her Keyblade Armour, she wears mostly a desaturated purple, with dark blue, black and silver sections, and highlights in a more yellowed grey. The shape of her helmet's faceguard is similar to that of a heart and the helmet's horns point downwards.
Powers and WeaponsEdit
Aqua is professionally trained in the art of swordsmanship and magic, unlike Sora and Riku who are self-trained. In combat, she specialises in the use of magic and has a great range of spells at her disposal, but she is not ill-equipped to attack directly. Her two exclusive Command Styles take advantage of her magical ability, with Spellweaver allowing her to use her Keyblade out of hand and Ghost Drive allowing her to warp around and attack enemies.
A few of her physical attacks and techniques are based on rhythmic gymnastics. She has access to the ability Doubleflight, allowing her to do a double-jump, and her version of a Dodge Roll is a full Cartwheel. Aqua's version of Break Time, a healing dance, is a baton routine using her Keyblade.
Her unique Keyblades are largely water-themed except for the Master Keeper, Eraqus's old Keyblade, which she retrieved from the Land of Departure. Aqua's other main Keyblade, Rainfell, is capable of being transformed into her Keyblade Glider, which she uses to travel between worlds.
- Kingdom Hearts: Birth by Sleep, 2010