|“||I still love that lonely little girl I met so long ago.||”|
–Kouta, confessing his feelings in the final anime episode
Kouta is the main male protagonist and the deuteragonist of the Elfen Lied series, second only to Lucy in central importance, born and raised originally in Hokkaido. He is the most important person to Lucy, and the tragic love of her life.
When he was somewhere between the ages of 10-12, Kouta; his sister Kanae and their father traveled to Kamakura in the Kanagawa Prefecture to spend the summer with his cousin Yuka and her mother. It is unknown who the siblings' mother was, and whether this was the cousins' first meeting is also unknown.
Some time after his arrival, Kouta decided to walk around the Tanzawa mountains around Kamakura. While in the mountains, he encountered a mysterious horned girl after she had buried a puppy she had cared for and then lost to cruel children. Noticing the small horns on her head, Kouta, unlike the children of the orphanage, was ecstatic over her unusual appearance, finding the horns "awesome." He quickly offered her his friendship, but she showed distrust and reluctance towards him, Kouta not knowing of just how much she'd been deceived and hurt by Humans before meeting him. A persistent Kouta made a promise that he would come back to the same patch of wilderness the next day, at the same time.
Unfortunately, Kouta wasn't able to fulfill his promise; his father wouldn't let him outside because of the recent murder of a group of orphans in the area. Some time later, he was able to sneak outside to meet the girl (whose name he never learned at this time). He arrived to find her having seemingly waited for him in the rain the whole time. Remembering the girl's distaste for the attention the horns brought her, Kouta presented her with a wool hat to cover them up. They agreed to meet up and play together the next day. To Kouta, this was a simple friendship with someone he saw as exciting and different. To the girl who would one day be called Lucy, it was an alien and exhilarating experience, and one whose ups and downs she was badly unprepared for.
Again, due to the recent, unexplained homicides (by now, entire families were being killed in their homes), Kouta's father refused to allow him outside. Three days later, on the last full day of their holiday, Kouta begged his father to let him go out to meet his friend. Kouta's father allowed him to leave, taking into account the lack of murders since the ones that initially concerned him.
Kouta went to the usual place where they met and there he met up with the girl, who had been waiting for him all that time, having almost given up hope. Because it was the last day he could stay with her, Kouta decided to take her to the zoo and spend all day with her. Her fascination with animals she had never had the chance to know of (such as elephants and giraffes) surprised Kouta, and he took delight in her joy from this, as well as an everyday frozen ice treat he bought. They enjoyed themselves all day, and this created a strong bond between them, stronger still for the girl who had never known anything like this before. Both of them were sad because of the little time they had together passed so quickly. What Kouta didn't know was that he was so important to her that the thought of his imminent departure crushed her heart.
When she learned he was going to a nearby festival, she begged to go with him, but he said that he promised to go with his cousin. At nightfall, as they were returning on the bus, the girl, in a trance-like state, arguing with an inner voice, began choking Kouta. When she woke up, she apologized, then startled him again as she asked him, if someday she couldn't stop killing, to kill her. Kouta was unable to connect this conversation to the recent murders, and soon after forgot about it.
When they had returned, the girl inquired Kouta as to his cousin's gender. Not wishing to hurt her feelings, Kouta lied and said his cousin was a boy. Kouta then went to the Kamakura beach with his cousin, Yuka, and his sister, Kanae, to play. Kanae collected shells to show her brother, but Kouta said they weren't pretty enough, prompting Kanae to kick him, swearing that she would seek better shells.
Upset about his impending return to Hokkaido, Yuka, developing a crush on Kouta, asked Kouta if he wanted to say anything to her before he left. At that age, somewhat ignorant of girls' feelings towards him, Kouta simply annoyed her by being unable to answer and was promptly scolded. It was at this point that Kanae returned with shinier shells, finally earning his praise. Later, Kouta realized he hadn't thought to ask the horned girl for her name, leaving it shrouded in mystery not just for him but for the audience as well.
Night came, and Kouta and Yuka went to the festival together as they agreed. During the festival Yuka began crying over her inability to cut out shapes at a model carving stall and hugged Kouta, begging him not to leave for Hokkaido. Kouta embraced her as well in order to console her, unaware that they were being watched by the girl from earlier. Moments later, people began to panic and run away, saying that a bomb had gone off. Concerned, Kouta's father panicked and called for the children, finding Kouta and Yuka quickly but becoming worried over Kanae's absence. Kanae appeared soon after, terrified and covered in blood, saying that a number of people had been killed in front of her by a horned girl. Kouta immediately thought of his friend but denounced Kanae's tale as being utterly fictitious. In any event, Kouta's father decided to take the first train back to Hokkaido, concerned that the 'bomber' might still be about. Saying goodbye to a tearful Yuka, Kouta promised that he would come visit her the next year, just before setting off. In the manga, Yuka and her mother saw the family off; In the anime, only Yuka was there.
On the train home, Kanae kept insisting her story was true and that a horned girl really did kill people at the festival despite Kouta brushing it off as a lie, while authorities insisted on the story of a bomb going off. When the aforementioned girl appeared in the train car, Kouta was surprised and happy to see her despite Kanae's alarm. Kanae defensively jumped in front of Kouta, trying to protect him from who she saw as a killer. Kouta angrily denied Kanae's account that his friend could be responsible for so many horrible deaths and finally slapped her, reducing his little sister to tears when he said he hated her. As she pleaded for him not to hate her, the horned girl tore Kanae in half with an unseen weapon, and soon after beheaded their father, before telling the horrified Kouta that Yuka would be next. In a mixture of grief and rage, Kouta assaulted her, demanding that she stop killing. Somewhere in his demeanor, she realized her hideous mistake. The girl ran away, leaving the traumatized Kouta alone and covered in blood, surrounded by the bodies of his sister and father.
What happened to Kouta between this point and his coming to Kamakura again is left up to speculation. Presumably, other family members cared for him in the period between his release from mental care and the start of the series. He had spoken to the girl about his grandmother in the present tense, but nothing more is said of her. All that's known for sure is that after the murder of his family, he repressed all memory of that summer trip to preserve his sanity. His new memories consisted of his father instead dying in a car accident and Kanae passing away from an extended illness. The anime briefly speaks of Kouta staying in a hospital for an extended period, but for just how long and what type of hospital it was is never clearly stated.
Returning to and reunions in Kamakura
Eight years later, he returned to Kamakura in the Kanagawa Prefecture to attend college and went to meet his cousin after arranging to stay with her family while at school. To her dismay, he did not seem to recall either those childhood times or her. While walking on the coast beach where they used to play many times in their childhood with Kanae), they encountered a young woman, with long pink hair, nude in the surf and completely amnesiac, with a childlike personality and horns on her head. Closer inspection revealed her horns were indeed real (as opposed to costumery), leading Kouta to flash back to a blurry, forgotten memory. Instead of taking her to the police, they decided to take her to Kouta´s new home at Maple House, the former restaurant Yuka's mother owned, where he would live rent-free as part of a maintenance agreement. They decided to name the girl they found "Nyu" after the only word she seemed able to speak.
At night, while Kouta was unpacking, the seashell Kanae got for him fell out of his bag. Yuka recognized the shell from the last day of their summer vacation, the same day his family was killed. Kouta's sad face while looking at the shell caught Nyu's attention, and thinking the shell is something bad, Nyu picked it up and promptly cracked it in half, much to the two cousins' shock. Kouta was instantly infuriated and began to shake Nyu, demanding to know why she did that. Nyu, terrified by his reaction, runs away from the house. Yuka goes after her after suggesting why Nyu did what she did, and that Kouta should honor Kanae's memory with something other than grief and bitterness.
After some time, Kouta decided to go after Yuka as well. When leaving, he encountered two policemen, who showed him a picture and asked if he saw the girl in it, whom he recognized as Nyu. Asking what she's accused of, Kouta is told by the younger policeman that she is a dangerous serial killer, though the second policeman claimed his partner is merely joking, and that the girl was just missing. Nevertheless, Kouta lies to them and goes to find Nyu before they do, not believing someone with her mental state could be a killer. He finds Nyu at the beach in the freezing water, and Yuka arrives shortly after. They realize Nyu fled there to get shells to replace the one she broke. Suddenly, Yuka takes a blow in head from a soldier searching for Nyu, that leaves her and then Kouta unconscious. In the manga, Kouta attempted to challenge the soldiers, only to be knocked out dismissively. In the anime, Kouta attempted to flee with Nyu, as Yuka was not present, but ends up knocked out as well.
At the hospital, Kouta's account of soldiers on the beach are dismissed by the police, who were, in fact, covering up for the activities of the Special Assault Team. This deception leads Kouta to distrust the police even further. Yuka told him she could not help him with discovering what happened, since she was knocked out very soon in the manga, and was not at the scene at all in the anime. Both expressed their worries about Nyu, who was otherwise engaged at the time.
After leaving the hospital, the pair is reunited with Nyu, unaware of where she was, or what she did, while away. Kouta makes an attempt to change Nyu's wet clothes without compromising her modesty, but this leads to a comically timed walk-in by an easily upset Yuka, who also presses him on what he recalls of her. Angered by his response, Yuka leaves, with an upset Yuka now in Nyu's clueless care. Returning to Maple House to check on them, Kouta relates to Yuka on the loss of his family, only for an upset Yuka to realize he truly cannot recall those times, as his account of how this happened differs from what she knows. This cements her decision to live with the pair at Maple House.
Life at Maple House
Shortly thereafter, a young girl came to visit Maple House to return an umbrella dropped by one of the residents on the night the soldiers attacked Nyu on the beach (Yuka in the manga, Nyu in the anime). Named Mayu, her words quickly made Kouta realize that she witnessed the events that the police deny and Yuka cannot recall. When Yuka returned, the two also quickly realized that something was amiss with Mayu, but the girl leaves with her small dog Wanta before they can act then and there.
Unbeknownst to anyone, Nyu was an alternate personality for Lucy, a powerful killer with an agenda to replace the Human race with beings like herself. She was the childhood friend who murdered his family, and as Lucy, she still remembered Kouta and continued to love and adore him. This love also spares, reluctantly at first, Yuka and the other residents from Lucy's wrath. Switching personas in front of the cousins and their young guest when Nyu is injured, Lucy departed with her personality recalling the events of eight years ago, but her Nyu side and Kouta himself still in the dark. Nyu's activities while away would affect Mayu as well. Injured in the midst of a fight between two Diclonius, Mayu, whose relationship with her family at home was deeply troubled instead had the hospital call Maple House, with Kouta picking her up and paying the bill, which Mayu promised to repay. Taking her back home for food and persuading her to stay for the night, neither Kouta nor Yuka could get Mayu to reveal anything about her home life. Finding that she had left the next morning, they realized (Yuka in the manga and Kouta in the anime) that they should see to Mayu's care and well-being themselves.
After speaking with a local beachfront vendor who had aided Mayu, they confirmed what they had suspected, that the young girl was a homeless runaway. With Nyu returned as mysteriously as she had left, the three prepared to take Mayu in more or less permanently. Once more, events differed between the two versions of the story right after this. In the manga, Mayu found many difficulties that made the hard life she'd gotten used to no longer possible, and reluctantly turned to Maple House as she had no other choice. In the anime, many of these same difficulties came at Mayu, who at last was confronted by policemen concerned for her safety and for her loitering on the beach. In this case, Kouta and Yuka showed up, claiming to be Mayu's family, there to retrieve her after an argument. The end results were the same. When Mayu came to Maple House, she was surprised by an offer to live there on a regular basis, a birthday cake provided by the vendor she'd befriended, and the return of her dog and at one time only friend, Wanta. Within a few weeks, Kouta and Yuka persuaded Mayu to reveal her home address. The two met with Mayu's mother and were privately shocked and concerned when the mother in effect signed over custody of Mayu to them without any sort of discussion. But they agreed to not discuss this out of courtesy to Mayu, and since this enabled her to attend a new school closer to them, it was an outcome they chose not to dispute. In short order, Mayu became a happier girl, with the others happier for her happiness. The problems of Nyu's childlike if not infantile behavior would have to be dealt with another way.
At some point, Kouta and Yuka decided to bring Nyu with them to their college classes, likely after undepicted events made leaving her alone at home unacceptable. Her horns hidden by bows, and her having learned to say one word besides 'Nyu', the two sought to keep her under watch but also out from scrutiny. This became difficult one day when Nyu encountered Lucy's sworn nemesis Bando in what mostly came to be a comical interlude. An encounter of a far more sinister kind awaited Kouta on a day that started with Yuka rousing him by way of kicking at him. Departing for a class, they found that their teacher was a Professor Kakuzawa, a man with a reputation equal parts sleazy, harsh and flaky. All this aside, none of them realized that not only was the Professor the son of the villainous Chief Kakuzawa, the prime enemy of the entire series, but also the one who had secretly engineered Lucy's bloody escape from the institute he once worked for.
After Nyu spoke up at precisely the wrong moment, Kakuzawa recognized the girl as Lucy. The fast-talking practiced liar convinced the cousins that he was Nyu's relation and threatened them with arrest for not reporting Nyu. Kouta and Yuka in effect surrendered custody of Nyu (which they never had legally in any event) and left her with her supposed 'Uncle'. Back home, a tearful Kouta found two more things wrong with the day in question. A sharp if a subtle comment from Mayu told him that an embarrassing incident with Nyu in the onsen was not forgotten, and had placed him in Mayu's sights as a possible menace, just as her sexually abusive stepfather had been. Then, to both his and Yuka's shame, Mayu simply questioned whether or not the Professor had told them the truth about being Nyu's uncle. Considering what a bad reputation the Professor had, Kouta went off to retrieve Nyu, lightly rebuffing Yuka's offer to join him. What he found back at the lab would have far-reaching implications for the manga series' final third.
A grim thread emerges
Upon reaching the Professor's lab, Kouta met Doctor Arakawa, the Professor's overwrought assistant, who confirmed Mayu's theory that the Professor had been lying since he didn't have a brother (although this was also not quite true either). But instead of finding Nyu, they found the Professor's body, his severed head nearby it, and that his head had small horns on it, though different to Nyu's. Outside their presence and possible knowledge, the Professor's effort to rape Nyu had morphed into an offer of alliance with the awakened Lucy, followed by a murderous rejection that would only be fully explained much later on. For the moment, Kouta accepted Arakawa's admonition to forget all he saw there while finding his paranoia amped up by her description of what happened to horned people. As she cleaned up the mess and informed the Professor's family, Kouta left, wondering again what had become of Nyu. Returning to Maple House, he later accepted Yuka's offer to travel with him while he looked for Nyu. For her part, Mayu (who subtly became more comfortable around him again, possibly due to his not menacing her) elected to check the beachfront with Wanta. In both versions, a sudden rainstorm forced Kouta and Yuka to seek shelter, as well as answers concerning each other.
Inside a rest shelter in the manga, and a shrine in the anime, the pair huddled for warmth, and eventually began kissing. Notably, the manga version almost reaches the explicit for how it affects the two of them. In either version, Kouta says that while he still cannot recall Yuka from their childhood, he recalls feelings about her, including caring for and liking her. This seemed to reassure Yuka to a degree. After some version-dependent embarrassment for Yuka, the two departed and found Nyu nearby in her Lucy persona. When Lucy pretended to be a coherent Nyu and tells them that she must go from their lives, Kouta protested and asks her to stay. Realizing that the truth is the only way to protect Kouta from the danger that follows her, Lucy attempted to give him closure by fully confessing who she really is. At the last minute, though, she lost her nerve and reverted to Nyu, who they finally took home again, to a happier if still not a peaceful Maple House.
Once back home, Nyu resumed a pattern of intrusiveness that upset Kouta's peace of mind and his relationship with Yuka, though it may have saved his relationship with Mayu. Waking up in his futon, Kouta was roused by Yuka, who pulled away his covers to find a nude Nyu cuddled up to him, something Kouta himself hadn't realized. Unfortunately for an enraged Yuka, Nyu became curious about her breasts and began to mercilessly grope Yuka, leaving her overcome and Kouta fixated on the alluring sight. Adding to the embarrassment, Mayu walked in on the sight, deciding that all adults are perverted. But curious Nyu briefly groped Mayu's immature body, only to walk away disappointed and leaving Mayu upset, for the grope, and for the opinion. While never stated in-story, this point seemed to be when Mayu stopped regarding Kouta as a direct possible menace, perhaps out of some recognition of Nyu's antics.
Yuka's irritation always seemed to travel in Kouta's direction, even in an incident like this, and so he was warned to be on his best behavior when a high school friend of hers came for a visit. She also directed him to fetch groceries and cleaning supplies. While complying, Kouta encountered a young woman whose skirt was caught by a gust of wind, revealing to her shame that she wore an adult diaper. Coming back home, later on, Kouta was mortified to find that the young woman he had encountered was in fact Nozomi, the friend Yuka had been expecting. Her nerves on edge, Nozomi was forced to flee as her bladder gave out again, exceeding the capacity of her current diaper without a ready replacement. Outside, Kouta and the others searched for her, with Kouta again finding her as she removed her diaper, though soiling her blouse in the process, leading everyone to know her secret. Thinking fast, Kouta knocked Nozomi into a puddle, obscuring her shame with a more understandable stain. Out of gratitude, Nozomi took the Yuka-blow meant to punish Kouta for pushing her in. Nozomi apologized for her cowardice, but Kouta admonished her not to think of herself in such a way. With his and Yuka's encouragement, Nozomi soon enchanted the entire household with her operatic voice. Nozomi developed a pronounced crush on Kouta as a result of his kindness, one of which Kouta seemed to remain unaware.
Kouta began to become concerned about the overdue return of Mayu and Wanta, out for a walk, but this was alleviated when Mayu returned with a new companion, a girl named Nana. To the household's shock, the young girl had horns just like Nyu, and Kouta began to pepper her with questions, hoping to solve the mystery (in his present-day memory) of where Nyu came from. But in fact, Nana was from the same facility as Lucy/Nyu and had been horrifically wounded by Lucy, and the mere sight of Nyu was enough to cause Nana to attack her, injuring Nyu and wrecking the house in her path. The sight of the Maple House residents, especially Kouta, instantly taking Nyu's side put Nana in tears and flight, with Mayu pursuing her.
While the attack upon Nyu was enough to awaken Lucy, she was feverish and exhausted, only able to be cared for by Kouta, and remembering troubling aspects of her life. Upon reflection, Lucy decided that Kouta could not be safe or happy when she was around, and so used her will to induce her own personality to recede entirely in favor of Nyu. Nyu, for her part, took Kouta's words about his regrets with Kanae and acted to aid him in a way only she could, or only she would ever likely think of.
When Kouta again found her, Nyu had cut her hair and was wearing clothes too small for her. She had done this in a sweet if an awkward effort to impersonate Kanae so that Kouta's deceased little sister could provide him with forgiveness for their last harsh words. A Kouta struck by the tender gesture (perhaps reinforced somewhere in his mind by who was doing this) gave Nyu a hug, one sadly witnessed by Yuka, whose doubts drove her crying to the beachfront, determined to never again go home to Maple House, and possibly even suicidal. In the midst of her despair, Kouta came and got her back, even going so far as to slap her across the face for worrying him so badly. As with Mayu, this incident had the unspoken effect of resolving Yuka's worries about Kouta, and for the remainder of the series, her own scolding and hitting of Kouta all but vanished. Yet Kouta would have another young lady to square matters with as soon as a few hours from then.
At Mayu's behest, Nana had returned to Maple House, and apologized for attacking Nyu (who she realized did not have Lucy's presence, a sense that Diclonius have to detect one another), but refused to come inside, still feeling she was the wronged party, and feeling she still needed to keep watch over Lucy's return. Perhaps made too much like each other, Nana and Kouta clashed until Mayu made staying in Maple House a challenge she pretended that she felt Nana could not handle. Kouta later joined this with some reverse psychology of his own, slowly leading up to the idea that Nana would have to contribute to the house with chores to pay her way. Within a day of enjoying simple creature comforts not available as a test subject, Nana was comfortable in Maple House and even happy. When she left suddenly to deal with the threat of [[|Mariko|another Diclonius]], the clash was entirely forgotten, or at least put aside, by Kouta, who left to retrieve her from the beachfront, his worry over young girls like Kanae overriding any other problems. What happened next defines a climactic point in the manga and the conclusion of the anime.
In the anime, when Kouta and Nyu arrived at the bridge to Enoshima Island, they found a barricade of police at minimum knocked out on the ground, possibly dead, in a scene that causes continuity problems. That aside, Kouta proceeded ahead of Nyu and found Nana, stripped and tormented by Mariko, who asked the permission of her handlers to kill him. The concern that Kouta and Nana showed for each other intrigued Mariko's overseer Shirakawa, who approached them. Unknown to Kouta, Nana protected him (and anyone else she targeted) by disabling Mariko's vectors, causing her and her control force to eventually withdraw. After Nana fell off the bridge (where she was recovered by her 'Papa' Kurama), Nyu made her way over, which panicked all of Mariko's group except for Mariko herself, since she could sense that Nyu was not Lucy, at least in the respects that mattered. While Shirakawa urged caution, Isobe acted precipitously and had the soldiers present fire on Nyu, which awakened Lucy. Kouta, only seeing Nyu, ignored Shirakawa's warnings about Lucy, until an annoyed Lucy split Shirakawa in two, killing her and shocking Kouta's dormant memories awake. Realizing that his friend is also the killer who murdered his family, Kouta grudgingly accepts Lucy's request that they meet later on when she has settled matters with her enemies. Her humming of the song Lilium doubly confirms how they once knew each other.
Unknown to Kouta, at that same time, Yuka and Mayu discussed him back at Maple House. The observant Mayu tells a nearly despondent Yuka that Kouta seems to favor helping girls without anywhere else to go. In turn, Yuka related at least part of the story of how Kouta lost his family, which surprised Mayu. Mayu also complimented both Kouta and Yuka, calling them the Papa and Mama of Maple House, a compliment her manga counterpart could not quite bring herself to say. Confident that everyone now missing would soon return, Mayu also observed that Yuka was in love with Kouta, something Yuka conceded.
After Lucy settled matters with people as varied as Bando, Mariko, Nana, and Isobe, she met Kouta by the stone steps of Jouju-in Temple, there to talk out what they could in the time Lucy had before the series' true antagonist would send his forces against her. Lucy attempted to explain her purpose in life, and how only the thought of her love for Kouta kept her from fulfilling it. Stating she must leave, Kouta attempted to stop her, stating his love for the little girl she once was, and for Nyu. Notably, despite certain accounts to the contrary, Kouta does not forgive her crimes in this version, stating outright that he can never do this. His tone is simply more sympathetic. While their talk ends with a kiss, it is one laced with regret at what could have been.
Still largely ignorant of Nyu's past with him and her true self, Kouta, Yuka and Mayu continued to live at Maple House, where they were joined by Yuka's friend Nozomi and Nana, a Diclonius girl like Nyu, who was the first to openly assert the danger Lucy presented. Though she was indeed wronged and maimed by Lucy and attacked Nyu in retaliation, no one but Nana and later Mayu knew the reason why. Nana was only allowed to live with them when they discovered she had nowhere else to go, and only under the stipulation that she apologize to Nyu and never attack her again. During the battle with Mariko, Nyu and Nana disappeared, leaving Kouta worried. When they returned, Nyu had lost her horns and began to develop a more mature personality. Events outside continued to build as the people who once held Nyu continued to seek to regain custody of her.
Through all this, Kouta, according to Nana's journal, continued to try and play protector to Maple House, with his results mixed but always appreciated. His relationship with the girls often meant him fetching them back and telling them how sad he would be if they left. Even Yuka began to calm from her anxious state, realizing his lack of memory of that important summer was due to trauma and not coldness. When the Unknown Man attacked Maple House, the group was dispersed for a time, once again reuniting in large part due to Kouta's determination that they should remain together and safe.
When Doctor Nousou and the Agent, backed up by clones of the Diclonius Mariko, led a full paramilitary assault on Maple House, Kouta attempted to end the situation by taking Nousou hostage. Unfortunately, he was then shot by the Agent, which triggered Nyu to not only develop longer horns than before but full-fledged vectors as well. As she bisected Cynthia, one of the Mariko clones, Kouta's memories came back to him in a flood, with him remembering how exactly his father and his sister died and who Lucy was. He swore vengeance against a newly woken up and shocked Lucy, but passed out before witnessing her fighting the remaining clones and subsequently being taken away by the Agent. Kouta was taken to the hospital, which he left prematurely upon sensing that Nyu had returned.
Kouta waits for Lucy on the beach, and when she notices he's still injured and goes to help him, he snaps at her to not touch him. However, he's not fit to walk long distances and relents to letting her carry him to the Sea Candle. While at the top of the tower, Lucy offers her apology for murdering Kouta's family and explains that an inner voice drove her to kill others. Kouta states that he can never forgive her for what she's done and dismisses her explanation of The Voice as something all people must deal with. Because both Nyu and Lucy share a body, he cannot bring himself to carry out his vengeance since that would mean losing Nyu too and instead offers Lucy a peaceful life at Maple House so long as she promises never to harm anyone ever again.
Although Lucy initially agrees, a chain of events lead to her instincts betraying her and Kouta is once again mortally wounded, this time by being shot by Kurama while trying to save Lucy's life. In retaliation for his sure death, she almost destroys the world in her despair, but with her body falling apart, she decides to use her powers to save him instead. Upon regaining consciousness, Kouta finds that Lucy is literally melting away from her last act of selflessness. Unfortunately, the violent personality she spoke of once again breaks through and starts assaulting the world once more. Kouta shoots and kills her at both Lucy and Nyu's urgings, thus stopping her violent rampage forever.
After Lucy/Nyu's death, life goes on at the Maple House, with Kouta helping Yuka, Mayu, Nana, and Nozomi repair the house. Every year, he goes to the spot where Lucy's puppy is buried to "wait" for her, mourning the friend he never truly knew. Several years pass and he has a daughter, Yuka's based on her appearance, and names her Nyuu in memory of his deceased friend. While visiting the grave with his daughter one year, he discovers the jade stone he gave Lucy and a letter she wrote for him that contains her real name buried near the grave marker. Through his tears, he laments the friend he never truly knew, finally having a name by which to remember her. As he is crying, Nyuu calls to a girl named 'Kaede' and two twin girls with ribbons in their hair appear nearby. The two girls are heavily implied to bear some connection to Lucy and Nyu, and tell Nyuu they've been waiting for their "special friend," to which Kouta finally turns around and smiles.
Kouta's role in the story is pivotal to the plot due to his importance to Lucy. His kindness toward her kept her from spiraling into a total meltdown, and apologizing to him motivates Lucy to continue living. He serves as the counter to the mistreatment she's faced.
Prior to the horrific events that changed his life, Kouta was a very outgoing child. He loved going out into the woods and countryside to draw, and easily befriended a young girl who, until then, had known only cruelty from her peers. He was even a disobedient child, as he snuck out to see his new friend despite his father forbidding him to do so because a murderer was on the loose. His wish to spare Lucy's feelings by telling her a white lie about Yuka's gender, unfortunately, led to the deaths of his father and sister by Lucy's hands, traumatizing him.
After the deaths of his family members, Kouta's personality changes completely. No mention is made again of his passion for drawing, and for most of the series, he is more introverted and blase toward most things unless they have to do with the welfare of the people he cares about. Losing his younger sister leads him to empathize with the unfortunate girls he and his cousin take in, as well as make him resistant to things which would tear the new family apart, such as going to the police to report they found an amnesiac girl with horns.
In the manga, Kouta's personality shifts to be angrier and wishing revenge against Lucy for the deaths of his family members once he remembers it was she who killed them. This change shows up again during him and Lucy's final confrontation in the manga, where he insists she not touches him (until he stumbles and she has to carry him) and he harshly rejects her notion that she was forced to listen to the DNA Voice within her. He never forgives her for the deaths of his sister and father, but ultimately admits that she could have a place with him and the others of the Maple House if she never kills again. The idea of losing a member of his family outweighs his wish for vengeance, and though his interactions with Lucy on the beach and on the Sea Candle make it apparent he still hates her and what she's done, he's willing to accept her as part of Nyu so he won't lose yet another person he cares for. He even takes a bullet meant for her, not wanting her to die like Kanae: with his last words to her being unkind ones.
In the anime, at least, this aggressive change in personality is hinted at during smaller moments, such as when he angrily bangs his fists against the table upon hearing the police lied to them and shaking Nyu when she breaks the seashell Kanae gave him. His treatment of Lucy's apology in the final episode isn't as harsh as it is in the manga either, as he states he loves who she once was and loves Nyu as well. While he does not forgive the murder in either version, his approach in the anime is a great deal more tender.
- It is only through Kouta's narration at the end of the manga that we learn of the war that followed Lucy's death.
- Kouta's name is sometimes romanized as Kohta, most notably in ADV's promotional materials.
- Kouta appears by himself on only four manga chapter covers, a surprising number for the series' secondary lead. However, male characters in all appear only a total of five times on these covers, excluding the cover cast shot of the final chapter.
- Besides the college where he was accepted, Kouta applied for fifteen other universities but was rejected from all of them.
- In his latest interview in a magazine published in August 2016, Lynn Okamoto says that although Kouta was a major male character, Kouta's roles in the story were too much passive and looked like a mere onlooker. Based on this thinking back, he says that Ryouta in Brynhildr played much proactive roles in order to protect the witches and other people.