Masataka Takayanagi is also in love with Aya, but she has shown no interest in him. However, she does respect him for his strength, skill, dedication, and typically calm nature. She eventually entrusts him to guard the computer chip that F is after.
Throughout the Manga, it is shown that Souichiro and Aya have some sort of mental connection between them that calls to the other when they are in trouble. This could be due to their powers complimenting each other, since Nagi's dragon's fist can collect and supply huge amounts of ki and Aya's dragon's eye can consume an unlimited supply of ki.
Aya fights with the Natsume family style just like her sister. It is called Natsume Goushin Ryuu.
Aya has an affinity for katanas, and is fairly skilled with them. She isn't as skilled as someone like Madoka Mawari, nor does she seem as good as her sister. Aya's first katana was shattered by Ryuzaki, and after a brief time in possession of Reiki, she borrows other swords.
Aya actually indicates Reiki is a part of her body, furthering the connection between the two. She has even recently managed to turn her hair into the Reiki, the method however is unclear.
As Masataka beats up on Souichiro after Souichiro attempted to sucker punch him, Aya "wakes him up" by yelling at him. She also refers to Masataka as a low level martial artist greatly disheartening him, which she doesn't understand. Souichiro uses the lunch Aya forced on him to do his "barrier" technique by shoving it in Masataka's face, and then punching him in the stomach. Now fully enraged by his rejection by Aya, Souichiro's rude treatment of a gift from Aya, and his cheap shot; Masataka attacks Souichiro in a berserker rage. Souichiro is pushed back to the wall by the enraged Masataka who gives him a severe beating, Maya and Aya tried to stop Masataka, but they are tossed away. In the Anime this is by far the most violent beating, at one point hitting Souichiro in the stomach so hard he vomits. In the end, Masataka misses his finishing blow (most likely intentionally), shattering the concrete wall behind Souichiro. This beating makes Souichiro make a promise to Aya to never lose again.
Later as Bob Makihara's motorcycle is burned, Souichiro and Bob realize Bob's girlfriend Chiaki is in danger. They rush to the laundry-mat to help, but Chiaki has already been assaulted (raped in the manga). They are subsequently beat down by an Executive Council member, Ryuzaki. Aya picks up on these events with her dragon eyes and rushes to help. She is too late, and is hit by Ryuzaki ripping her shirt open after he breaks her katana on his way out.
As Souichiro joins the Juken Club and is trained by Maya. Aya starts to grow increasingly paranoid of the relationship between Souichiro and her sister. It did not help of what vision was shown to her by her dragon eyes.
The group later gets attacked at a bowling alley and Aya is isolated after an argument with her sister regarding Souichiro. She is attacked by Tagami, an Executive Council member who fears her potential power. Given Tagami's weapon is a staff she moves up the stairwell to a narrow space to limit his movements. Unfortunately Tagami can split his staff into a multi-section weapon and Aya takes some damage, before she moves the fight to the roof. Aya's dragon eyes awaken and she starts to become over-enthusiastic to the fight as she gives into the dragon. She mercilessly beats Tagami, knowing every move he will make before he makes it. Despite the fact she hears his thoughts, and knows his bones are breaking she can't stop herself and nearly kills him. Afterward she is very torn up about her actions, until Souichiro reassures her. She later tries to take on Mitsuomi with Tagami's staff, but Mitsuomi uses the Muscle Bomb to shatter the staff and knock her down with out actually moving himself. Later as her dragon eyes activate, he merely flicks her in the forehead, but it's enough to knock her unconscious.
As her sword was shattered by Ryuzaki she elects to borrow a new one from her sister, she fails to tell her sister that however. Maya is quite surprised to find the family's heir loom, Reiki missing. Once she realizes Aya has taken it she is quite concerned. Reiki had played a large role in driving her brother Shin crazy, eventually leading to his death. As word gets out the school enters an uproar, when Mitsuomi Takayanagi the Executive Council President finds out he agrees to help search for Aya, despite his conflict with the Juken Club.
Aya meanwhile doesn't understand the significance of her possession of Reiki and thinks her sister is just picking on her. She ask Masataka Takayanagi to let her stay at his place for a while. As he has a crush on her, and as no one has told him what was going on he of course agrees. While at Masataka's Aya sees her brother's ghost coming to take Reiki away from her. He says it will only bring her sadness most likely destroying her like it did him , but she insists she wants to get stronger eventually convincing him to leave it. In the end Maya ends up fighting her sister over the whole thing, Aya loses and Maya takes Reiki back. Despite this, after some encouragement from Souichiro, Aya gets in good spirits again.
Mitsuomi also agrees to put off all aggression until the school's annual election tournament.
There are 12 families that have historically support the Takayangi family, but have broken up. The families are split into white and red feathers, the Red Feather Families all have a special power. Natsume was one of the Red Feather Families with the Dragon Eyes as the family's power. The new alliance of the heads of families has formed supposedly under Mitsuomi and call themselves 'F' (although all 12 have not joined). Despite Mitsuomi's order to wait for the tournament, F attacks the Juken club anyway. It is later revealed they don't follow Mitsuomi, but Souichiro's estranged father, Sohaku Kago.
Much later a boy named Mouki Enmi shows up at the Natsume house, claiming his home was attacked. It turns out Enmi is one of the 36 branch families, a branch of the Natsume family in this case and thus he has a similar power to the dragon eyes. This causes the Red Wing Resonance Effect allowing Aya to use her powers more easily. As Mouki is kidnapped by men on motorcycles, Aya and Souichiro hunt down the men on a scooter using Aya's dragon eyes to find all the shortcuts through town. She defeats the men and takes Mouki back. It turns out the assault on the Enmi family, was done by the F member, Jushi Mataza Tsumuji. Aya, Souichiro, Mouki and the stow away Shinichirō Kurei, head to Kyushu to investigate.
There they encounter Yorihira Tsumuji, Mataza's father who assists them initially. Turns out F is after the Enmi family scroll, more specifically a computer chip hidden with the scroll. A huge conflict breaks out between Yorihira, and Mataza with Aya, Souichiro and Mouki trapped in the middle. This culminates in a battle between Mataza and Souichiro, one so fast paced Aya can't intervene even with her dragon eyes working perfectly for her. In the end the victory goes to Souichiro, but he is driven crazy by his "Dragon" and attacks Aya and the others. He is stopped by his mother who loses her arm in the process of stopping him.
The story jumps to the start of the tournament, and Aya has cut off some of her hair. As she looks at Souichiro on their way home one day, one of her dragon eyes awakens and she sees Souichiro morph into Sohaku. Suddenly he returns to normal and she is left confused of what to do. It seems she is the only one who knows Souhaku's eye was placed in Souichiro, but it's unknown if she is helping keep his personality dominant or Sohaku is just lying low for now.
As the tournament starts the Juken Club gets pinned down by their first round opponents, the Archery Club. Aya and the others are helpless as they can't get to the Archery Club's position. Masataka slept in on accident and on his way to the fight encounters Tagami. Tagami shows Masataka a shortcut to the Archery Club's position, where Masataka crushes the leaders crossbow and wins the round for the team.
Later as Kagesada Sugano fights the Jujutsu Club's captain, Aya follows a trail of ki from the captain to Nokimi Mayutsubo. She tries to attack Nokimi, but the floor is cut out from under her by Hirohiko Myouun Kabane. Hirohiko tries to convince Aya not to fight, suggesting she would be better off leaving to plan how to deal with all the people under Nokimi's influence. Aya, however, realizes that Nokimi contained the queen that controls all those insects Nokimi uses. If the queen was destroyed, the others insects would probably lose their control or even die. This forces Hirohiko to attack, however Aya comprehends the nature of his swords and cuts them down, as well as the floor underneath him.
The fight moves down to the next level and despite her knowing the weakness of Hirohiko's blades, Aya is helpless against his increased aggressiveness. Hirohiko maintains his unwillingness to kill Aya, insisting she retreat; but Maya's condition inspires Aya to continue. She uses her family's secret technique in an attempt to turn the tide against Hirohiko. Surprisingly Hirohiko uses all the dust Aya's attack kicked up to form a shield blocking her attack. He then forms armor as well and resumes his attack on her. Hirohiko shatters Aya's katana, leaving her desperate and wondering how he got so strong.
Aya's Dragon's Eye reveals the answer to her; Hirohiko is motivated by the desire to end the war so he can marry Mitsuiro. The new knowledge makes Aya start to like Hirohiko even more, since the two are fairly similar. However Aya is motivated again, in a move similar to the Kabane Blade, Aya forms ki around her hair to make an imitation Reiki. Aya remembers a puzzle her mother used to make her do blindfolded, thinking it was some kind of training. Strangley, one piece is always missing in the puzzle. Hirohiko is unsure if what Aya made is the real Reiki or not, even though he's sure its impossible to just make it appear like that. He quickly shatters the imitation Reiki, but since Aya's hair, blood etc. are mixed in with the dust he's using she can manipulate it as well. Aya starts to take apart Hirohiko's armor, but Souichiro arrives and interrupts the fight.
Kagesada's fight is over, apparently in a double knock out. The entire Juken Club arrives on the roof and Hirohiko elects to let his protection of Nokimi lapse. He plans to tell Mitsuomi that since Aya alone gave him so much trouble, he didn't want to try to take on the whole Juken Club as well. Nokimi is hit in the stomach forcing her to cough up her queen insect.
Aya thanks Hirohiko, claiming the fight made her feel like she had just received decades of training. Aya even wonders if that was Hirohiko's goal from the start, to train her. Aya then realizes that much like her puzzle she wasn't able to see Hirohiko's "final piece", She notices there were blades Hirohiko made under the floor ready to attack her at anytime. Realizing Hirohiko held back all the way to the end Aya feels totally beaten as she wasn't actually able to hurt him. Feeling depressed Souichiro goes to cheer her up; Aya then kisses him saying that if it were not for him, she would never have be able to do anything to Kabane.