"I won't let you kill people."
Enju Aihara is a small girl with several prominent features, the most noticeable being her long crimson hair. She keeps it in two knee-length ponytails, emphasizing her small body and leaving the back of her neck slightly bare. Enju has two large, black tags tying her hair with what appear to be bunny designs printed on them. Her forehead is covered by bangs split in the middle, each side reaching to her eyes and covering the sides of her cheekbones. Enju's eyes are rather soft, but do have a slight edge to them. They have large red irises and very small, black pupils. Enju has a rather small mouth and nose.
Enju's clothes consist of a small orange hooded-sweater with orange and red square designs on the inside. The front bottom ends are folded upwards and held by buttons. The sweater has a short zipper with an oversized tag. Underneath the sweater, Enju wears a long, white dress (partially resembling a camisole). She wears a thigh-length skirt held up by a large, thick belt. Enju wears knee high boots with extremely thick, heavy, black soles which she utilizes to crush her enemies. The uppers of the boots are black and dark purple in the manga. In the anime, however, they are black with red accents and use zippers instead of laces and straps. On top of that, the soles in the anime are slightly smaller. The toes of Enju's boots appear to be white rubber.
She is also rather lively, as Mai, a school friend, claims she is always smiling regardless of the situation. However, she feels pain when young girls like her are also mistreated because of the blood running through their veins. This is further stated when Rentaro ignores a cursed child being mistreated in front of his eyes: Enju confronts him with her anger purring in the air violently.
Enju has openly shown jealously towards any girl that gets close to Rentaro such as Kayo Senju, Seitenshi , and even Kisara Tendo . She also has a flat-chest inferiority complex, as she feels offended whenever someone points out her flat-chest  and even squeeze Kisara's breasts and complements on them. Regardless, Enju does not hold grudges that easily and is more willing to make friends. In fact, she happens to be a very forgiving girl at heart and even willing to befriend former enemies, as she manages to forgive and befriend Tina Sprout despite the fact that Tina has brutally injured Enju earlier. 
When Enju was first introduced to Rentaro, the former assaulted the latter in an act of defense, lacking trust in humans at the time; held prisoner within the International Initiator Supervising Organization by homo sapiens. After Rentaro introduced her to her new home, Enju's emotionless appearance rapidly changed for the better. Eventually, Enju happily dined along with Rentaro, her distrust in humans slowly fading away. As time progressed, she became an Initiator and began to work for Tendo Civil Security Corporation alongside Rentaro.
Civil Security arcEdit
Enju informs Rentaro that ten minutes prior to his arrival she encountered the Gastrea before it changed form, with the infected man being Sumiaki Okajima; whom tells her to apologize to his wife and child before turning into a Spider Gastrea in his stead. Fighting it and getting several injuries upon starting, she claims that she was hit by a sticky substance that grounded her and prevented her from helping Rentaro when she saw him entering the area with Tadashima.
Currently conversing with Tadashima, the man questions the flare in Enju's eyes the moment she entered the battle, with her reply being that she is an Initiator. She pulls on Rentaro's arm and, without warning, kisses him. Rentaro moves back as she admits that when she was not around he fought bravely, but kicks him in the crotch for leaving her behind. Once on the ground, Rentaro notes the injury on Enju's back, prompting Tadashima to asks if they need an ambulance, but is denied as she rapidly recovers by using her Initiator abilities. Shortly thereafter, Enju calls Rentaro and tells him the Gastrea's dying words, receiving a shallow look from the boy. Minutes later, they part ways with Tadashima as Enju reminds Rentaro about the limited sale, rushing to the location. Along the way, Enju notes the height of the Monolith, which are meant to keep Gastrea at bay due to its strong magnetic force created from Varanium. When suddenly, they get a call from Tadashima, who informs them that they forgot the reward, causing Enju to sadden as they keep walking back to the company.
The Cursed Children arcEdit
At night time, Enju and Rentaro eat dinner, with Enju delighted with the latter's cooking abilities and even questioning if she will one day learn to cook like him. However, after telling her that shell will learn soon enough, he announces that it's time for her shots. She rolls the table to the corner and extends her arm out in front of Rentaro, who inserts an erosion shot into her. Lost in his thoughts, Rentaro is asked by Enju if it's already over, with him responding positively. The two then get ready for bed, but Enju expects something else as she holds her arms out and tells Rentaro that her heart is ready, but the teen simply falls asleep. Angry, Enju attacks Rentaro. The next morning, an energetic Enju brings a bike with her, ready to school when suddenly the television captures their attention. Seitenshi along with Kikunojyo Tendo appear live, shocking both Enju and Rentaro.
As they watch the news, Enju notices that the man standing next to Seitenshi is Rentaro's adoptive father, prompting her to question Rentaro. However, before she can watch the entire news, she is pulled by Rentaro who claims that if they keep watching television they will be late for school. On their way to school, she comments on how the scenery looks like "Rome" as they ride down several beautiful streets. Along the way, Enju begins to wave hello to civilians, causing Rentaro to ask her if she is happy at school, with Enju giving him a positive reply. When they finally arrive to school, she is told by Rentaro to keep her identity a secret, but she affirms that she knows already as her friend Mai approaches her; walking to class together afterwards.
In high spirits, Enju brings numerous items to Rentaro's attention whilst at a store, but receives negative replies to all but a small bracelet which seems to intrigue his curiosity. Enju explains that it's from a popular anime where girls in the show wear them to prove their friendship, and that when it cracks, it means the user is telling a lie. She eagerly tells Rentaro the price, causing him to put it back where it was. Soon however, Enju takes it back and says that she will use her allowance money to pay for it as she rushes to the cashiers. The two leave the store and walk about on the streets, trying out the newly bought item as they hear Seitenshi speaking in a near television. Seconds later, when Rentaro stops walking, Enju calls for his attention asking if anything is wrong. She is told that if a law is passed, Gastrea infected children will no longer have to be abandoned; Enju blushes and smiles at Rentaro—filled with excitement. However, their moment is short-lived when a girl that is being persecuted approaches their direction, turning out to be a Cursed Child.
She watches as the girl gets captured, and then reaches her arm out to Rentaro. Though, in return, Rentaro slaps her hand away. Enju, in disbelief, lowers her head as the police takes her away whilst badmouthing the Cursed Children. Afterwards, when they leave, Enju confronts Rentaro for his earlier actions, prompting Rentaro to take her to a nearby alley and explaining to her that it was impossible for him to do anything. However, Enju claims that those are just excuses, as she knows that he could have done something. She begins to cry as Rentaro lowers himself and asks her if she knows the girl, to which she responds affirmatively, telling him that when she lived in the outer area she would see her once in a while. Putting his hand on her head, Rentaro tells Enju to head home first, which she does.
At night time, Enju comes rushing in to save Rentaro when he is attacked by Kohina Hiruko and Kagetane Hiruko. She is called a small fry by Kohina, but in return calls her rude and states her name and model: Rabbit Initiator. Kohina, on the other hand, tells her that she is Model Mantis. She stands next to Rentaro as he is asked by Kagetane to join him, causing her to look at him in worry. Much to her happiness however, he refuses and Kagetane leaves with Kohina. When they leave Enju reveals to Rentaro that Kagetane's Initiator is strong and is unsure of victory if matched against her.
The next day, with the rumors of Enju being a cursed child, she leaves school and goes to where many cursed children are sheltered by Matsuzaki. In the morning, Enju heads to school but is neglected by her school peers as they isolate themselves from her. Following said events, outside of class a group of students circle around her.
Legacy of the Seven Stars arcEdit
Enju, encompassed by several of her school peers, is called a monster by an enraged boy who claims that his father's leg was eaten by a Gastrea and died because of the said action while at the same time physically violating his own wife. Enju, however, defends herself and states that she is human, only to be told to stop pretending and getting pushed back by the kid. She sees Mai, but the latter simply turns her head and walks away, leaving Enju in dismay. She begins to walk back slowly until bumping into Rentaro. He tells her that they will switch schools, but she refuses to do so as she will not leave the friends in her current school. However Rentaro admits that they are no longer her friends, as she is hugged by him. Seconds later, she asks if it's now impossible for her to rebuild her friendship with the school kids, with Rentaro responding affirmatively. Enju then cries as she asks him where she should geply, Kisara calls him and sends a helicopter to pick them both up.
Aboard the helicopter she hears Rentaro say that he found the Gastrea, prompting Enju to open the back door and, surprisingly, jump straight towards the Gastrea and take it to the ground.
Fighting the Spider Gastrea, Enju remembers the words her peers threw at her, filling her with anger. She quickly kills the Gastrea, but in a blind rage continues to repeatedly crush its dead corpse. She is brought back to her senses by a shocked Rentaro, who hears her say that she "can do it"; protect the Tokyo Area and everyone at school. Sobbing, she hugs Rentaro as he tells her that he is her family and that he will show her the way. The two hug and promise to stay with each other. As they get ready to take the case back, Kohina appears and ambushes Enju, as well as Kagetane pushing Rentaro away from the object. She glares at Kohina. Enju, fighting Kohina, is told to run away by a wounded Rentaro as he shoots her opponent. At first she refuses, but does as she is ordered and leaves him behind seconds later. Running through the forest, Enju, with tears running down her face, looks for help. She finds none other than Shougen and his Initiator, and frantically begs them for help.
She returns to the hospital with Rentaro, and leaves him at the care of the doctors. After a day and a half, when he wakes up, she comes to the hospital along with Kisara. When she enters the room, she jumps him and hugs him happily. Refusing to let go when he asks to. After Rentaro begins to eat and converse with Kisara, a jealous Enju interrupts their conversation and tells Rentaro that she has something she wishes to show him, leaving the hospital to go home. Sometime later, Enju returns and angrily yells at Kisara and Rentaro for leaving the hospital room and going to the roof. Before she can continue her rant, she tells Rentaro that her bag was left at the gates of her home and with a letter telling her to "work hard." Thus, Enju continues; it is the reason why she will work hard and will protect everyone by returning the case. Looking at Rentaro, she tells him that she is ready to go whenever he is. After gathering their supplies and heading to the place of departure, Enju and Rentaro come across Shougen and Kayo. When they leave, Kayo winks at Rentaro; angering her. However, she dismisses it and readies for their departure alongside Rentaro.
When they leave and arrive to a dark cave, Enju questions Rentaro if he can turn the flashlight on, with the latter informing her that if they keep it on for long they will be found. However, he turns it on after admitting that they need it inside the cave they are in; shocked by the scenery of the Unexplored Territory. She is told that they will go to the nearby streets, with her following after him. As soon as they exit the cave, she jumps on Rentaro and tells him to stay silent, saving him from a Stage IV Gastrea in the process. She gets up and congratulates herself for saving them both, but hears an explosion near them that makes the IV Gastrea return. She grabs Rentaro and begins to run away from the Gastrea. Being told that he is counting on her, Enju picks up her speed and begins to jump. However, the Gastrea proves to be quick. But Enju is faster as she outruns it and jumps off a cliff. Seconds later, she informs Rentaro that they are landing. Now on the ground she takes the league as she states that she can defeat anything. Much to her shock, however, a gun is pointed at her head; the holder turns out to be Kayo asking for Enju whilst seemingly injured.
Shortly thereafter, Enju angrily states that she will not acknowledge Kayo, claiming that she can heal injuries of her magnitude in a matter of seconds. She then stands behind a wall as Rentaro tends to Kayo's injuries. Afterwards, when Kayo receives a call from Shougen, who tells her that they have sighted Kagetane and Kohina, the three quickly head to his location. However, as soon as they reach it, they are confronted by a deer Gastrea and several other Gastrea ambushing them from all directions. But before Enju can do anything, Kayo defeats them with her intelligence alone, shocking them when she reveals that she is model Dolphin.
Enju walks behind Kayo as they approach the port, stopping momentarily when they hear Kayo inform them that she shall stay behind and protect the port from the wild Gastrea in the forest. Enju can only watch as Rentaro begins to argue with her, telling her that it would be better if she were the one to go fight Kagetane. However, shock is written all over Enju's face when Kayo slaps Rentaro and chastises him for his lack of analyzation. Sequentially, Enju holds her hands together when Kayo is asked by Rentaro if she does not wish to keep on living, only to hear the Initiator tell Rentaro in return that dying was never an order. As she walks towards the forest, Kayo tells both Enju and Rentaro to take care of Shougen for her.
The two head to the port whilst Kayo stays behind. Along the way, Enju confesses to Rentaro that she is happy to be his Initiator, receiving a positive reply from the Promoter. Finally reaching the port, they look around; but find nothing. Seconds later, they hear a stop and turn their heads, met by Shougen. The two rejoice at the thought of victory, but as they do so, and as Shougen gets closer to them, they notice that his own Buster Sword has been buried in his back. They look around and notice the dead bodies, understanding that Civil Security has fallen to Kagetane. However, Enju's attention returns to Shougen when the senseless man thinks Kayo is in front of him, asking her to bring him his sword. Enju picks the sword's handle up and gives it to him, rapidly being told by the man to take him to Kagetane so he can finish his battle. Enju grabs his hand, walking as Shougen begins to reveal his true feelings towards Kayo and the way they are treated; calling her righteous. Enju releases his hand when the man takes his final breath, telling Rentaro that they must apologize to Kayo. Rentaro agrees, but reminds Enju that they must finish their final battle. The two arrive near an ocean at the port, where Kagetane and Kohina stand. Enju intensely glares at the opposing Initiator, getting ready for battle.
Enju is told by Rentaro to brace herself for the upcoming battle, to which she responds to in agreement. Assuming their battle stance, Enju hears Kagetane claim that they shall make their final battle grand, shortly enough witnessing the man's Maximum Pain placed into effect. She grabs Rentaro and jumps high in the air in an attempt to avoid the attack. However, Enju is met by Kohina, who emerges from within the cloud of smoke, and commences their fight elsewhere as Rentaro lands on the ground near Kagetane. Meanwhile being watched by an Electronic Eye.
Turning her attention towards Rentaro's Varanium limbs, Enju recalls him vowing to never use that power again, but is subsequently asked if she believes in him, to which she replies affirmatively. She then watches as he utterly dominates the masked man, only to have her opponent: Kohina, flee their scuffle to protect Kagetane. However, she quickly reaches Rentaro and protects him from her blades by using her foot, kicking her away. Rapidly, she grabs Rentaro and takes off to another location whilst an excited Kagetane shoots at them with his guns. Reaching a stop, Enju tells Rentaro that it's time to initiate their plan; seemingly heading to attack Kohina but in reality targets Kagetane as Rentaro attacks Kohina with a Flashbang. Enju uses the distraction to move away from Kagetane and jump at Kohina, destroying her blades with a powerful kick and sending the Initiator into a nearby body of water. Rapidly turning to attack Kagetane in conjunction with Rentaro, Enju strikes yet another vigorous kick that sends Kagetane flying towards Kohina's direction.
The two look at the noted direction, but as Rentaro releases a sigh of relief, Enju's arm begins to bleed due to the Varanium bullets Kagetane assaulted her with. Quickly being treated, Enju can only ponder if they really won. Rentaro attempts to reassure her, but as he does so, Kagetane and Kohina reappear. Enju instantly grabs Rentaro and moves to another location, but their opponents prove to be quicker as they arrive first. Kagetane begins to reveal his motives for unleashing a Stage V Gastrea, claiming that for Mechanical Soldiers like them fighting is the only reason to their existence. He attempts to pair himself with Rentaro, but Enju interrupts him and states that they are nothing alike; they still love their peers despite being mistreated. As she ceases her statement, Kohina appears behind her with her broken blades, telling her to die. Enju attempts to kick her, but fails. Just as she is pushed towards Kagetane, who is holding his gun in his hand, she closes her eyes at the thought of being hit by Black Bullets. Albeit, Rentaro steps in front of her and takes the bullets in her place. Enju orders him to move, but he refuses. She then watches in terror as her Promoter injects himself with something that causes him to releases a terrifying howl.
The bullets within Rentaro's body slowly fall out, leading Enju to frighteningly murmur his name. She then watches as Rentaro attacks Kagetane, shortly enough she herself preventing Kohina from aiding her father. Enju begins to feel a strong pressure from Rentaro's location, causing her to turn her head towards his direction and pleadingly yell for him to get way. Screaming his name yet again once Kagetane's Endless Scream makes contact, Enju hastily runs to his side, asking if he is alright. However, she arrives in front of Rentaro and remains immobile as she eyes Rentaro's condition. As tears fall down from her eyes, Enju vigorously shouts her Promoter's name as she steps into a puddle of blood created from the fatal wound Rentaro acquired from the technique.
She continues to stand by Rentaro when Kohina arrives behind her, ignoring her presence as tears continue to descend down her face. Regardless, Kohina kicks her far from Rentaro, with Kagetane immediately shooting Black Bullets to kill Enju.
Enju tells Rentaro that she will fight against Tina during the second time that Tina attacks, and jumps away to confront her. She is shot down by Tina using her remote control machine guns, which Tina destroyed afterword using plastic explosives. Enju is taken to the hospital, where she is treated and is put to sleep for two days.
The Third Kanto War arcEdit
A stage four Gastrea attaches itself to Monolith 32, injecting a Varanium-corroding fluid that will destroy the barrier and allow Gastrea to eradicate the Japan Area, bringing on a Great Extinction. Enju and Rentaro are tasked to form a party of Civil Officers. Absent for the first recruitment, Enju helps Rentaro to find an old friend in Shouma Nagisawa, who has also become a civil officer. Midori Fuse, a model cat initiator is also introduced, and Enju and Yuzuki spend a deal of time fawning over their new friend. However, monolith 32 collapses ahead of schedule, and Enju and the others are forced to go to war.
Initiator (イニシエーター Inishiētā): With the Gastrea blood in her body, Enju has gained superhuman abilities; thus becoming a member of Civil Security and receiving a Promoter as her partner. Enju Aihara is a Model Rabbit Initiator, which means the fluid ingested by her mother belonged to that of a Rabbit Gastrea, the majority of her strength is concentrated in her legs, which is why when engaging in combat she proceeds to make use of kicks. Furthermore, her legs are hardened to the point of being able to break steel as is the case in the fight between her and Kohina Hiruko.
- Initiator's Ability: Physique: Enju has proven herself to be a great combatant when it comes to fighting Gastrea of low and high stages, quickly annihilating a Stage I Gastrea with a single kick to the eye, as well as sending it several feet back with the impact of the kick. This is further supported when she jumps many feet from the ground and crashes into a Gastrea, taking it to the ground with her without any sign of fatigue.
- Initiator's Ability: Agility: Enju takes pride in her own speed, outrunning an extremely fast Gastrea whilst carrying Rentaro on her back; at the same time commenting on how she is undoubtedly faster. She also displays ludicrous jumping abilities as she is able to jump several feet in the sky even with a person on her back, as well as preform many jumps on tree branches and not lose any energy in the process. Further; when she fights with a Gastrea that attacked her with liquid that glued her to the ground, Enju portrays remarkable speed as she un-glues herself and kills the Gastrea in mere seconds.
- Initiator's Ability: Recovery: As a result of the Gastrea blood in her veins, Enju can recover her own wounds at an amazing rate. When she does so, smoke covers the wound and, after it clears, the spot appears unharmed.
Enju enjoys Rentaro's company, and has admitted on numerous occasions that she loves him emotionally; humorously ignored at the time. Said statement is further proven true when the young girl lands a kiss on Rentaro's lips. When she kills a spider type Gastrea after Rentaro had mangled with it, she comments on his bravery and admits to being shocked that he was able to keep his own against a Gastrea. Despite this, however, she scolds him for dropping his guard in battle too quickly. In addition, she kicks him in the groin whilst reminding him that he left her behind, calling herself his fiancé at the same time. Rentaro, on the other hand, views Enju as nothing more than family, treating her like a little sister and often defending her from the people that have called her a "monster" or humanity's enemy. The two share a strong bond that is only emphasized when the Enju is badmouthed by the kids at her school; Rentaro comes to her side rapidly and reminds her that he will always be there for her to show her "the way."
Mai is one of Enju's many friends. They attend school together and are usually seen walking to class side by side, with Mai noting Enju's charismatic persona and enjoying her presence. When Enju's true identity surfaced, Mai was notably the only kid at her school that did not insult her; rather, ran away confused and hid her dilemma from the others. However, later on when Civil Security prepares to engage Kagetane Hiruko in combat, she is shown fixing Enju's bag beforehand and dropping it off at her house without revealing herself. In addition, she adds a "work hard" note inside; which inspires Enju incredibly.
Tina Sprout is a fellow Initiator. Despite Enju having being injured at the hands of Tina's weaponry, some time later; following Tina's fight with Rentaro, both girls are seen to be on friendly terms and getting along fairly well. Enju considers Tina her protege. However, Enju also considers Tina a rival for Rentaro.
A fellow Initiator, and member of Rentaro's adjuvant. Although the two just met, Enju, just like Yuzuki Katagiri seemed interested and were curious upon seeing her cat-like ears. Regardless, she treats her as a friend.
Kohina Hiruko is Enju's rival, with the two engaging in combat the many times they have come near one another. When they first met, Enju was called a small fry by the young Initiator when she interrupted her battle with Rentaro, only to instantly return the insult and introduce herself. Since said time, Kohina has grown noticeably interested in fighting Enju and killing her, even to the point of admitting that she will remember her name. When Enju and Rentaro locate the Gastrea they were ordered to kill, Kohina, along with her father, appears and rapidly aims to kill Enju, preventing her from helping Rentaro in the process. When Enju runs away from their battle, she loses her cool and even stabs Rentaro in the back for allowing her said action, asking her father if she could chase after Enju and kill her.
Appearances in Other MediaEdit
A Day of Civil SecuritiesEdit
Before Rentaro can open the doors to Tendo Civil Security Corporation, Enju comes jumping onto him from the inside. He asks her about her school day, but she dismisses it and states that it doesn't matter; in comparison to what is happening to Kisara, who comes near them and happily welcomes Rentaro back with a nya. Enju and Rentaro, both shocked, look at her is disbelief. Enju calls Rentaro and informs him that seconds before he arrived Kisara solely spoke about killing him. Whilst there, she hears Kisara state that they must defeat some nearby Gastrea to save the company. Before she can continue speaking, an explosion is heard, causing Enju to grab Rentaro and head to the scene. When they arrive to the location, Enju is told by Kayo to stand back as the Gastrea are too strong for her. However, she contradicts her claim when she kills one in a mere amount of seconds. Before long, she and the others team up to fight the Stage II Gastrea.
- (To Sumiaki Okajima) "I won't let you kill people."
- (To Rentaro Satomi) "Rentaro, you let your guard down too early. I couldn't bear to watch."
- (To Rentaro Satomi) "In that situation, when I, the Initiator, wasn't around, you bravely fought against the enemy. Rentaro, you were kinda cool."
- (To Rentaro Satomi) "Hey, hey. How can Rentaro cook something so delicious? It's like magic."
- (To Rentaro Satomi) "My heart...is prepared..."
- (To Rentaro Satomi) "Rentaro...I know. I will do my very best to not let anyone in class find out that I am one of the Cursed Children. Of course I will also be cautious when I'm in front of a lot of people."
- (To Mai) "Oh. Good morning, Mai-chan. It's great that you're energetic today too."
- (About the "Gastrea New Law) "I'm excited!"
- (To Rentaro Satomi) "Those are just excuses! If Rentaro wanted to, he could have helped her! Rentaro is an ally of justice. There's nothing that Rentaro can't do!"
Battles & EventsEdit
- Enju Aihara vs. Sumiaki Okajima
- Rentaro Satomi, Enju Aihara & Tadashima vs. Sumiaki Okajima
- Enju Aihara vs. Kohina Hiruko
- Enju Aihara vs. The Original Gastrea
- Rentaro Satomi & Enju Aihara vs. Kagetane Hiruko & Kohina Hiruko
- Rentaro Satomi, Enju Aihara, Shougen Ikuma & Kayo Senju vs. Stage II Gastrea
|Initiators||Enju Aihara • Tina Sprout • Yuzuki Katagiri • Asaka Mibu • Yulia Kochenkova|
|Deceased||Kayo Senju • Midori Fuse• Hotaru Kouro|
|Male||Rentaro Satomi • Kikunojō Tendo • Sōgen Saitake • Tamaki Katagiri • Sogen Saitake|
|Female||Enju Aihara • Kisara Tendo • Seitenshi • Tina Sprout • Yuzuki Katagiri • Asaka Mibu • Miori Shiba|
|Left||Kagetane Hiruko • Kohina Hiruko|
|Deceased||Shougen Ikuma • Kayo Senju • Midori Fuse • Shouma Nagisawa|