Aqua

Aqua is one of the main protagonists of Kingdom Hearts Birth by Sleep. She is also the protagonist of Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-, Aqua was a Keyblade wielder years before Sora was. Like Terra and Ventus, it is her dream to become a Keyblade Master, a dream she is the only one of the three to accomplish.

Before Kingdom Hearts Birth by Sleep
Aqua, alongside Terra, was one of Eraqus's pupils. Like Terra, Aqua also had a dream of becoming a Keyblade Master.

One day, a suspicious man named Master Xehanort arrived and gave Eraqus a new apprentice to work with, a boy named Ventus. Terra called out to Aqua and told her that a new apprentice had just arrived. Aqua and Terra tried to converse with Ven and asked him about why he wanted to train to become a Keyblade Master. The questions troubled Ven to the point that he couldn't take the pressure. He fainted and shocked Aqua and Terra.

Eraqus told Aqua and Terra that the reason Ven fainted was that he had lost his memories. Aqua decided to look after Ven, in case he woke up. Many days passed and, despite Ven being unable to awaken, Aqua did not abandon him. One day, Aqua saw Ven open his eyes and regain consciousness. Overjoyed, she quickly informed a worried Terra and Master Eraqus.

Since that day, Aqua developed a very close relationship with Ventus, acting much like his older sister and becoming very protective of him. Over the years, Aqua, Terra, and Ven forged a strong bond with each other.

Kingdom Hearts Birth by Sleep
One night, Ven, Terra, and Aqua watch a meteor shower together. After commenting that Ven and Terra would make the weirdest brothers, Aqua gives them each a good luck charm called a Wayfinder she made herself, saving one for herself.

The next day, she takes the Mark of Mastery exam along with Terra, and becomes a Keyblade Master, although Terra fails due to his inability to control his darkness. After Terra and Ventus left, Aqua was the last apprentice to be sent by Eraqus to bring Ventus back to the Land of Departure. Before she left, Eraqus wanted to ask Aqua to keep an eye on Terra, to make sure he is alright and stays safe from the darkness in his heart. If Terra's heart would become too close to the darkness, Eraqus needed Aqua to bring Terra back immediately.

Aqua meets Terra in the Castle of Dreams, where she learns that Master Xehanort is looking for hearts of pure light, but she is comforted to hear that Terra had learned there that believing in a dream has the power to hold back the darkness. However, her faith in Terra is shaken when she arrives in Enchanted Dominion to learn that, according to Maleficent, Terra willingly helped steal Aurora's heart for her. Aqua later catches sight of Terra in the Lanes Between and pursues him to Radiant Garden, but loses track of him there.

Aqua meets Mickey Mouse and the young Princess of Heart, Kairi, who touched Aqua's Keyblade in fright, unintentionally performing a Bequeathing. Aqua and Mickey protect her from a group of Unversed, and in return, Kairi gives Aqua flowers, which becomes the Keyblade Destiny's Embrace. Aqua also places a protective charm on Kairi's necklace to help her in the future, believing that their meeting may not have been a coincidence. This charm would later transport Kairi to Destiny Islands where she would be with someone who would always protect her, while Ansem believed it was because Kairi, as a Princess, was naturally drawn to the Keybearer.

Aqua later meets up with Terra and Ventus, but the reunion is short-lived as they team up to battle a massive Unversed. They manage to defeat it, but things take a turn for the worse. Terra and Aqua begin to argue about Master Eraqus's orders, revealing to Terra that she was sent to watch him. Hurt by this, Terra leaves, and Ventus calls Aqua awful, claiming that she has let her new status as a Keyblade master go to her head. He then leaves to find Terra, as Aqua stays to contemplate.

After meeting Merlin at his house, Aqua goes to the town square and encounters the enigmatic Vanitas, who taunts her by inquiring about Ventus and if he has gotten stronger. When Aqua asks what he means, Vanitas attacks, and the pair fight a vicious battle. Aqua emerges victorious, but Vanitas simply leaves via Corridor of Darkness, making an ambiguous comment about her being his backup plan. Aqua then resolves to stop Vanitas to protect Ventus and Terra. Ventus then appears, asking to go with Aqua. At first, she is harsh with him and he appears discouraged. She softens and tells him she doesn't want to put him 'in harm's way', and departs not long after.

Aqua's faith in Terra is restored upon her visits to Olympus Coliseum and Deep Space. In Olympus Coliseum, Aqua learns that Hades attempted to trick Terra into being his warrior of darkness, but Terra instead saved Zack when Hades decided to use the warrior instead. In Deep Space, Aqua learns from Dr. Jumba that Terra considered his Wayfinder a precious reminder of their friendship, and had even inspired Experiment 626 to start making friends.

While in Neverland, Aqua encounters Peter Pan and the Lost Boys, joining them on their treasure hunt. They later find their treasure chest, filled with wooden swords and Ventus's wooden Keyblade. Peter Pan tells Aqua that Ventus left the toy there as he no longer needed it. Aqua then senses someone nearby and goes off to investigate. She then encounters Vanitas again, this time with Ventus's cherished Wooden Keyblade. The dark enigma cruelly mocks Aqua's actions and snaps the toy weapon in two. Greatly enraged by this, Aqua battles and defeats him again, but is left exhausted by the fight and passes out. While unconscious, she reminisces about the first starry night she spent with Terra and Ventus. She soon recovers and leaves Neverland.

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; though she initially intends to grant Sora the power to use the Keyblade, she decides against it upon discovering that Terra had already done it for Riku, not wishing to put the two innocent children through the ordeals she and Terra have faced.

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.

A short conversation with Ventus takes place there, one where he states that if he does become the χ-blade, he wants the two of them to "put an end to me". Aqua appears horrified, but Master Xehanort makes an appearance and tells about the history of the Keyblade War. Afterward, they attack, and a great battle takes place. Xehanort holds Ven over the edge of a cliff where Aqua can see, he freezes the boy and drops him; however, she manages to catch him. After fighting Braig and then Ventus under Vanitas's influence, the X-blade is destroyed and she is flung into the Lanes Between, unconscious. Mickey finds her and Ventus drifting there and brings them both to Yen Sid's Tower, where it is revealed to her that Ventus has lost his heart. She takes Ven back to the Land of Departure and places his sleeping body in a throne. She takes Eraqus's Keyblade and transforms the world into Castle Oblivion to keep Ventus safe. Afterward, she says her goodbyes to Ven, fondly stroking his hair, and leaves. She then tracks down the possessed Terra to Radiant Garden.

Failing to bring Terra back to his senses, Aqua fights and defeats Xehanort; subsequently, Xehanort stabs himself in the chest with his own Keyblade in an attempt to lock Terra out as a horrified Aqua looks on. As Terra-Xehanort falls through a portal into the Realm of Darkness, Aqua dives in after him but quickly realizes that she will be unable to save them both. Instead, Aqua sacrifices her armor and Keyblade to save the dark being that had once been her dear friend, sending him back into the Realm of Light while she remains behind. Now stuck in the Realm of Darkness, Aqua is attacked by several giant Heartless and decides to just allow them to destroy her, but is saved by Terra and Ventus's Keyblades. She is then reminded of the people she is connected to. With renewed trust in her friends, Aqua looks at her Wayfinder.



Aqua's Wayfinder begins to mysteriously glow. As she travels in the realm, she sees a large circle of the light from above her, only for a powerful column of darkness to shoot out of it in front of her. Her Wayfinder stops glowing. Seemingly unshaken by this, she presses forward and encounters several Shadows, Neoshadows, and Darkballs. After traveling deeper into the Realm of Darkness, Aqua senses something stalking her, and comes face to face with a large Heartless that attacks her. To prevent it from attacking her, she uses a Fire spell, only for it to leap over her. Getting a closer look at it, Aqua determines it is not an Unversed and takes a battle stance to fight it. After destroying the Heartless, Aqua continues walking, eventually coming to a clearing and looking up. Surprised, she recognizes the Castle of Dreams surrounded by clouds of darkness.

Between Kingdom Hearts Birth by Sleep and Kingdom Hearts
Realizing that the Castle of Dreams has been swallowed by the darkness, Aqua roams the Realm of Darkness to uncover the source behind the strange occurrences. Furthermore, she also notices that time does not pass in the Realm of Darkness, and therefore does not know what is happening in the Realm of Light. In the remains of the Castle of Dreams, Aqua encounters an illusion of Terra. Realizing that the denizens of the world have not fallen to darkness, she resolves to press on. Arriving in the remains of Dwarf Woodlands, she encounters an illusion of Ventus and battles the phantom Aqua inside the Magic Mirror. After breaking out of the Mirror, she pursues visions of Terra and Ventus in the remains of Enchanted Dominion, battling hordes of Darksides in the process. To her surprise, Terra speaks with her, explaining that he has become part of the darkness. Xehanort uses Terra's connections to Aqua to force her to reveal Ventus's location, but Terra battles Xehanort, forcing Xehanort to summon the Dark Figure's hands to drag Aqua further into the Realm of Darkness.

Aqua prepares to become one with the darkness, but she is rescued by King Mickey. After Mickey explains his mission to save the Realm of Light from the Heartless, the two locate the Kingdom Key D behind the door in the secret place in the remains of Destiny Islands. Aqua and Mickey realize they are on the opposite side of the Door to Darkness. Aqua and Mickey prepare to help Sora and Riku seal the Door to Darkness. When a Demon Tide attacks Riku, Aqua sacrifices herself by staying on the darkness side of the door to save him. The Demon Tide thrusts her back to the island shore, separating her from Riku and Mickey because the door in the secret place has been sealed and has disappeared from Mickey's side. While fighting the Demon Tide, Aqua vows to guide other lost souls lost in the Realm of Darkness. After its defeat, Aqua rests on the shore, watching the sky. Once Sora saves the worlds, Aqua remains in the Realm of Darkness and not Destiny Islands, as she is not originally from the island, though Master's Defender is returned alongside Destiny Islands.

Kingdom Hearts II


Aqua's armor and Keyblade reside in the Chamber of Repose, a room constructed by Ansem's apprentices under Radiant Garden for an 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.

Kingdom Hearts coded
Aqua is alluded to by Data-Naminé as one of those connected to Sora's heart and needs his help, appearing as one of Data-Naminé's mental images. Later on, after Mickey informs Yen Sid that they have located Ventus's heart, Yen Sid concludes that Terra is the only one left to find, as the two had already located Aqua.

Kingdom Hearts 3D: Dream Drop Distance
Mickey mentions Aqua when he suggests that he help Sora and Riku inside the Sleeping Worlds by following his heart's path, as Aqua told him long ago.

When Sora arrives at The World That Never Was, he is caught by the Organization and placed within a nightmare in which he chases after memories of Riku and Kairi. When he catches up to them at the Contorted City, the phantoms suddenly take the form of Terra and Aqua, while Sora himself takes on Ventus's appearance. Sora is confused, but the phantoms grasp his hand before turning back into Riku and Kairi and walking off again. As Riku attempts to wake Sora on his own side of the dream, Sora recalls when Aqua came to Destiny Islands and nearly wakes up.

However, Ansem appears within Sora's dream at the last second and thrusts him back into the nightmare. Xigbar and Xemnas reappear within the nightmare to taunt him and lead him into despair by explaining the inevitability of their plan and playing on his insecurities, but a defiant Sora proclaims that while he may not have been chosen by the Keyblade, he will always be proud to be there for his friends, including Aqua and all the others.

Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-
After Riku brings Kairi to the Mysterious Tower, Mickey tells the story of how he found Aqua and teamed up with her to find the Kingdom Key D and seal the Door to Darkness. A frustrated Riku demands to know why Mickey didn't tell him sooner, but Mickey clarifies that he had to respect her choice, his claims bolstered by Yen Sid's insistence that had Riku found out sooner, he and Sora would have staged a fruitless rescue mission. Yen Sid then assigns Riku and Mickey the mission to rescue Aqua.

Blank Points
Aqua wanders into the End of Sea, where she meets Ansem the Wise, who was cast into the Realm when his machine exploded. Ansem the Wise reveals to Aqua that the Realm of Light nearly fell to Darkness more than once over the course of the last decade, though it was saved by an exceptionally Keyblade wielder named Sora. Knowing that Sora will rescue her and her friends, Aqua sheds a single tear, while uttering Sora's name with renewed hope.

Kingdom Hearts III
Shortly after meeting Ansem the Wise, Ansem, Seeker of Darkness arrives on the shores of the End of Sea and demands information from Ansem the Wise regarding a girl who had undergone experimentation alongside Xehanort to unlock her forgotten memories. Aqua attempts to defend Ansem the Wise, but she is easily dispatched by Ansem's guardian without her Keyblade. Concerned for Aqua's safety, Ansem the Wise relents and leaves with Ansem, but not before the latter darkens Aqua's heart and casts her out into the sea, leading to her transformation into "Anti-Aqua".

Later, Riku and Mickey re-enter the Realm of Darkness to find Aqua, but after following her trail to the End of Sea, they find that Aqua is missing and are instead attacked by the Demon Tower. Anti-Aqua, who had been controlling the Demon Tower, reveals herself after Mickey is disarmed, picking up his Keyblade. Mickey recognizes her, but she says that he was too late and tells Mickey and Riku of the endless despair and loneliness she had endured within the Realm of Darkness. Believing herself to have been foolish for ever believing that someone would come to save her, Aqua has the Demon Tower attack Riku, but Sora intervenes, having found the Master's Defender in Destiny Islands and used it to create a path to Aqua. Sora then proceeds to fight Aqua himself, cleansing her of the Darkness and helping her to finally return to the Realm of Light.

Rather than taking time to recover, Aqua has Sora, Donald, and Goofy accompany her to Castle Oblivion, wanting to return to Ventus's side. Using Master's Defender, she unlocks Castle Oblivion's Keyhole, returning it to the former glory of the Land of Departure. The group finds the sleeping Ventus in the main chamber, though Aqua is quick to realize his heart had never returned to him in her absence. Vanitas, who had been following the group, interjects with the intent of a reunion with Ventus. Aqua is quick to attack Vanitas, but when Sora offers to help her take Vanitas down, Aqua isolates herself with a barrier in order to prove herself to Sora. When Aqua gains the upper hand, Vanitas instead targets Ventus and attempts to break the barrier between them. Aqua instead takes the brunt of Vanitas' attack, allowing Vanitas the opportunity to take Aqua's heart. This stirs Ventus's heart within Sora, and with Sora's help, his heart returns to his body. Launching himself at Vanitas, Ventus saves Aqua, and Vanitas retreats into darkness.

Reunited, the five heroes head back to the Mysterious Tower, where Mickey apologizes for being unable to find Terra, but Aqua is certain that she and Ventus will be able to get him back. Riku also thanks Aqua for saving him when he was in the Realm of Darkness the first time, expressing regret for being too inexperienced to help her back then. Aqua is impressed that Riku and Mickey were both made Keyblade Masters, but also notes that Sora has not changed since they last met, leading the latter to scratch his head in confusion. When Yen Sid acknowledges Lea and Kairi as Keyblade wielders, Aqua immediately recognizes Kairi as the same girl that she cast a spell on when she visited Radiant Garden.

With their clash against the Seekers of Darkness imminent, Aqua and Ventus take time to star-gaze outside. Ventus uses this moment to admit to Aqua that while he was sleeping, he would have dreams of her, Terra, Sora, and the others. He also expressed memories of weird animal creatures. Aqua says that she's been places too, but she can't wait until things are back to normal. The two hold both of their Wayfinders to the sky, promising to share their stories with Terra after they save him.

The following day, Aqua joins the rest of the heroes as they go to the Keyblade Graveyard. Ventus sees Terra in the middle of the wasteland, but Aqua immediately realizes that it is not Terra. Her suspicions are confirmed when Terra's hair goes from brown to white, revealing himself to be Terra-Xehanort. Mickey concludes Terra-Xehanort is the thirteenth member of the Real Organization. Terra-Xehanort tells them that they will lose this fight, that all their hearts will be torn apart one by one. Nonetheless, Terra-Xehanort assures them the χ-Blade will be forged. Terra-Xehanort attacks both Lea and Ventus, removing them from combat, and while Donald destroys Terra-Xehanort with Zettaflare, the Demon Tide (which Aqua hallucinates is made of Anti-Aquas) proceeds to take advantage of their weakness and eliminate Aqua, Ventus, Mickey, Donald, Goofy, Lea, and Kairi. While Sora is distraught over the loss of his friends and yields to the Demon Tower, Riku defends his friend long enough to re-inspire hope in Sora's Heart before both are consumed by the Darkness as well.

Thanks to Kairi, Sora is able to maintain his existence in The Final World. When he is restored, he is returned to the moment in which he and Riku were consumed by Darkness, at which point Sora reaches out to Riku's Heart and is guided to him as a Lich attempts to draw Riku's Heart into the deepest depths of Darkness. Sora manages to release Riku's heart, alongside Aqua's and the others, battling the Lich time and time again in order to restore his fallen friends.

When Kairi guides Sora back to the Keyblade Graveyard, the group re-initiates their encounter with Terra-Xehanort, only when Terra-Xehanort attempts to attack Ventus, the Lingering Will intervenes, having been guided to the Guardians of Light by Naminé. Seeing the Lingering Will struggle in the battle, Ven moves in to help, but Aqua stops him, saying they need to handle the army of Heartless, Nobodies, and Unversed coming from behind them. Then, when it seems darkest, Sora is aided by the light of the past in taking down the Demon Tide. Yen Sid then takes this opportunity to cast back the Heartless in order to allow the Guardians of Light to proceed, with Donald and Goofy staying behind in order to help.

The Guardians of Light are subsequently separated by Xehanort when he raises a labyrinth around them. Fighting his way to his friends, Sora finds Aqua and Ventus fighting against Terra-Xehanort and Vanitas. With Sora's help, Aqua and Ventus are able to take Vanitas down. The three then attempt to reach out to Terra once more, but Xehanort uses his control over Terra's body to bind Aqua, Sora, and Ventus in chains. Intent on destroying them once and for all, Terra-Xehanort lifts Aqua and Ventus high into the sky and lets them fall.

Breaking through Xehanort's control, Terra reveals himself to be the guardian used as a weapon by Terra-Xehanort and Ansem, swooping in to save Aqua and Ventus just in time. Afterward, the guardian restrains Terra-Xehanort before it rips off the bandages covering its mouth and declares that it will set things right. Sora then steps in to unlock Terra-Xehanort's heart, in order to release Terra's Heart from Xehanort's control and allow the guardian to reclaim Terra's body, restoring him. Aqua, Terra, and Ventus then share in a tearful reunion, happy to be together again for the first time in over a decade.

After Master Xehanort successfully summons the χ-Blade and unlocks Kingdom Hearts, Aqua aids Sora in trapping Xehanort, who acts as a portal himself due to his existence transcending both space and time - something his younger self had unintentionally revealed to Riku during the Mark of Mastery. Aqua remains in the Keyblade Graveyard while Sora uses the portal to fight Xehanort, alongside Mickey, Riku, Roxas, Xion, Lea, Ventus, and Terra, in order to close Kingdom Hearts.

Following Xehanort's defeat, Aqua journeys through the portal to Scala ad Caelum alongside the other Guardians of Light. Terra begins to walk towards Xehanort while Aqua holds his hand to try to hold him back, believing Terra was planning to get revenge for what Xehanort did. Upon receiving a look of reassurance of Terra, Aqua let go and it was then Eraqus's Heart emerges from Terra's and demands that Xehanort hand over the χ-Blade. After some convincing, Xehanort relinquishes the χ-Blade to Sora, at which point Eraqus turns his attention to his former pupils - apologizing to them for everything he'd put them through in a tearful reunion before allowing his Heart to move on alongside Xehanort's. With everything as it should be, Sora uses the χ-Blade to bring them all back to the Realm of Light.

After some time, Aqua joins Terra, Ventus, Riku, Mickey, Donald, Goofy, Lea, Isa, Xion, Roxas, Hayner, Pence, Olette, and a newly restored Naminé in a fun day at the beach, though Kairi, who Sora had helped restore, remains separated from the group with Sora, who then disappears.

Sometime after this, Sora's friends split up their efforts to find him with Terra, Aqua, and Ventus looking for Sora in the Realm of Darkness, donning on their Keyblade armors as they depart.

The Gathering
Aqua, in her Keyblade armor, meets with Terra and Ventus at the Keyblade Graveyard and watches as an unknown enigma approaches.

Super Smash Bros. Ultimate
Aqua makes a cameo in  as one of the Stations in the Dive to the Heart sections of and as an obtainable  in Sora's.

Design


According to Tetsuya Nomura, she is approximately 18 years old.

Aqua has a tall and slender figure, about as thin as Ventus and standing a few inches shorter than Terra. She has blue eyes and medium-length blue hair, mostly parted to her left. She wears a black and navy blue, high-collared halter top, a black corset with two pairs of white laces and black shorts. She has two pink straps intersecting over her chest, with a silver badge similar to badges also worn by Ven and Terra over the intersection. 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 black stockings reaching about halfway up her thighs, leaving a small area of bare skin. There are two strips of blue cloth draped over each of her hips, along with a smaller, white strip of cloth tied around her waist and draped in the same manner. Her silver boots are pointed and armored, 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 , 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 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.

Her name is Latin for "water", while 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).

Personality
Aqua bears some similarities to Kairi and Sora, primarily in her sisterly affection for her closest friends, especially towards the younger Ventus. This is displayed by when she makes lucky charms for them, does everything in her power to protect Ventus, her confidence that Terra will overcome the darkness, and when she strands herself in the Realm of Darkness in order to save him, an act which could potentially doom herself forever, showing she is incredibly selfless. Aqua is shown to be very sociable with children, quickly befriending Kairi, Sora, and Riku.

Aqua is remarkably calm and dead-set on her goals, and only threats on her loved ones seem to make her lose her composure. Although, like Sora, Aqua is comically insecure in a romantic sense, so when Zack asks her out on a date, she becomes completely flustered and desperately tries to compose herself. She also quickly changes the subject when Hercules asks why her face is red.

Aqua is typically modest, only calling herself "Master Aqua" before she fights Terra-Xehanort, and acting very respectful toward elders and authorities, such as Master Eraqus, Queen Minnie and the Grand Councilwoman.

Like Eraqus, Aqua is also strict, stubborn and overprotective, which sometimes makes her seem condescending. She always worries about Ventus because of his age and lack of experience, ordering him to go home whenever she finds him without giving him a chance to prove himself.

Despite her flaws, when the situation demands it, Aqua's overall skill, determination, intelligence and kindness make her the most reliable and competent out of Eraqus's apprentices.

When briefly overtaken by darkness, however, Aqua loses any sense of her usual altruism, becoming angry, bitter, and cruel. She is particularly resentful of Mickey, whom she accuses of abandoning her in the Realm of Darkness for over a decade, saying that the fear and loneliness she suffered has left her feeling nothing but misery and despair. Nevertheless, once Sora restores her heart to the light, Aqua returns to her noble, loving, and forgiving self.

Aqua's time in the Dark World has left some psychological scarring, and she immediately gave up upon seeing the enormous storm of Heartless and even hallucinated seeing them as Phantom Aquas, not even resisting when the Demon Tide sucked her up.

Keyblade and fighting style
Aqua is described by Tetsuya Nomura as being "tricky". In terms of physical ability, she is the most balanced out of the three main protagonists of Kingdom Hearts Birth by Sleep, with decent strength, speed, agility, and range. She is neither the slowest nor the fastest of the trio, but her thin frame makes her a difficult target. Unlike Terra and Ventus, she blocks using Barrier, effectively giving Aqua a 360° defensive zone.

Aqua has very few exclusive s, consisting of Barrier Surge, Wishing Edge, and her most powerful attack command, Magic Hour. Her personal finish commands include the Magic Pulse series, Heat Slash 2, Ice Burst, and her ultimate finisher, Teleport Spike.

Magic
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 displays superior skill to both Terra and Ventus, as well as later Keyblade users, such as Sora and Riku. Aqua has a wide variety of Magic Commands. She has her own special variations of the Fire, Ice, and Thunder spells. Fire spells include Triple Firaga, Firaga Burst, and Raging Storm. Ice spells include Triple Blizzaga,, and Ice Barrage. A Thunder spell she can use is Thundaga Shot. She can also use Seeker Mine, and has a few unique magnet spells like Energy Magnet, Munny Magnet, and D-Link Magnet. She is also able to use Teleport in both offensive and defensive ways, being able to effortlessly dodge attacks or to land devastating surprise attacks on her enemy. She is also able to craft several copies of herself and use them either as a distraction or as a powerful offensive tool. Finally, she can conjure spheres of light using the Reflect element or Magical orbs with elemental characteristics with Magic Pulse. Before her fight with Vanitas in the Land of Departure, she also showed herself capable of conjuring up an invisible barrier to keep Sora, Donald, and Goofy away, though it was not impenetrable and could be destroyed by a newly-awakened Ventus.

Miscellaneous
Beside a variety of these abilities usable by all three or two of the protagonists in Kingdom Hearts Birth by Sleep, Aqua has access to two unique Command Styles and three exclusive Shotlocks. Her first exclusive Command Style is Spellweaver, which hovers her Keyblade in midair, swiftly attacking enemies while enhancing her magic capabilities as well. Her second style is Ghost Drive, a second level style which allows her to warp around enemies, attacking them at high speeds while using after-image illusions and tricky movements to her advantage.

Her exclusive Shotlocks are Bubble Blaster, Prism Rain, and Lightbloom.

Aqua has access to the evasion technique, Cartwheel, as well an offensive variant, Firewheel. She can also use Doubleflight, allowing her to jump once and jump again in midair. Lastly, she can use Teleport, allowing her to warp behind an enemy, dodging its attack.

King Mickey describes Aqua as strong, comparing her positively with Sora.

D-Link
Aqua becomes a D-Link for Terra and Ventus after they receive Aqua's handmade Wayfinders. While in link with Aqua, the player can utilize powerful magic attacks.

Weapons
Aqua's exclusive Keychains generally share a water-theme and are primarily focused on magical strength; in fact, her Brightcrest is one of the most magically-powerful Keychains in the game. Her Keyblade is of medium length, between those of Ventus and Terra. Aqua starts off with her personal "Rainfell", but after visiting 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 "Master's Defender", her former Master's Keyblade, which she had retrieved earlier. After the final defeat of Master Xehanort, Aqua wields her Rainfell once again, using it to open a portal to the Realm of Darkness. Small petals appear when she summons her Keyblade.