|“||This place... It's the only place I've ever called home.||”|
–Mayu, in the twelfth anime episode
Neither version of the series reveals anything about the fate of Mayu's biological father. At some point, her mother became disinterested and detached from concerns about her daughter. Mayu either did not realize this or did not understand the depth and breadth of the disconnect, which either was always there or eventually became total. Within a year of the start of the series, her mother married a man she referred to as a 'new papa,' indicating that the first father had once been a presence in their lives. In rapid short order, Mayu was sexually abused by her new Stepfather, sometimes to the point of sodomy. Enduring this in silence for an unknown duration, she told her mother about the abuse, only to hear her mother express bitter jealousy of the "attention" Mayu was receiving. Realizing she meant nothing to her mother, Mayu refused her stepfather's demands and ran away that very night, with only the clothes on her back (Mayu's skirt a casualty of her stepfather's demands before she resisted) only to find homelessness almost as great a problem. Fleeing to Enoshima Island, she was forced to survive on bread crumbs and whatever she might be able to find. Lonely and depressed, likely suicidal as well, she stopped her final wade into the ocean, finding a puppy and calling him Wanta. Like Lucy years before, Mayu even gave him food at her expense and stayed in a wood-pile shelter on the beachfront. The two all but lived on bread crusts and crumbs thrown out by a local vendor, who kindly pretended these were just a snack for Wanta. While a hungry and cold existence, the pair found it bearable so long as they had each other.
One rainy night, Mayu awoke to her customary hunger, and then heard the sound of gunshots and screams on the beach. A girl she did not know came running by her, confused and crying. When she arrived at the source of the noises, she found a severely wounded soldier with his eyes bleeding and his arm cut off, in shock and agony. Calming him down by out-screaming his rapid-fire expletives, Mayu tied off his severed arm's stump and called for an ambulance to come and get him. She also found an umbrella lost by Yuka, bearing the address of Maple House. When she returned to the beach after making the call, she found the man, named Bando, had vanished.
Meeting Kouta and Yuka
The next day, she went to Maple House to give Yuka back her umbrella (whose umbrella it was depends on the version). Kouta, who had been misled by the local police about what had happened there, ultimately including Bando's maiming, realized that she was a witness, and asked her to answer some questions, since he, Yuka and Nyu were attacked at that same time. Mayu was unable to answer most of his questions, and when Kouta asked for information about how they cold call her, a nervous Mayu ran off, concerning Kouta and Yuka. Before she left, she unknowingly saw the childlike Nyu shift into the murderous Lucy, with the trio saved only by Lucy's childhood connection with Kouta. Heading outside the house, Mayu also suffered a brief panic when she saw that Wanta's leash had been cut, in a fake-out scene common to both versions, by Lucy as she left the house. With Wanta still nearby, Mayu left, determined to resume the cold, miserable existence the two had known, feeling it still safer than trusting again.
Soon after, while eating the bread crumbs and crusts for the day, she heard a noise near Jouju-in Cemetery. Investigating, she interrupted a battle between Lucy, who she recognized from Maple House, and another horned girl sent out to retrieve her. Because of her distraction, Lucy gained the upper hand, and so Mayu witnessed Nana's brutal dismembering by Lucy, who also knocked her unconscious, perhaps not killing her because of her association with Kouta. Mayu would later dismiss all this as a dream, somewhat repressing the memory. Because of the blow took when she landed, authorities took Mayu to the hospital, but having no means to pay the bill, she called the only people she knew - Kouta and Yuka. When Kouta arrived, he asked her why she didn't call her parents, instead, but she only responded that she would pay him back. Taken back to Maple House, Mayu saw Nyu and briefly remembered what happened with Lucy and Nana, but again chose to believe it was just a dream. Mayu took dinner with them, even staying the night. When they asked if she had run away from home, Mayu refused to answer. The next morning she had left, leaving a note of thanks. Still concerned, Kouta and Yuka (differing by version) decided the only thing to do was take Mayu in, so they could know she was safe. To this end, they spoke with the bread vendor, learning that she was homeless, as they likely already suspected. Further, her very avoidance of the subject told them (mostly Yuka) that she could not return home. In the meantime, Lucy reverted to Nyu and returned home, her connection to Mayu's injuries remaining unknown.
Believing firmly that the beach was now her real home, Mayu's luck took a turn for the worse. A woman claiming to be Wanta's real owner appeared and took Wanta away, brusquely telling Mayu to not get near "her" dog again.
Completely devastated, Mayu made an effort not to cry, as this day was also her birthday. She suddenly remembered it was the last day the Bakery Merchant would be there and decided to thank her for everything she did. The woman said that she didn't do much for her and that she had told the residents of Maple House what she knew about Mayu when they came there looking for her. Now cut off from a food source, Mayu returned to her shelter, but soon a policeman warned her of beach flooding. Having lost her food supply, her only friend and her place to sleep, Mayu reluctantly decided to go to Maple House. Thinking nobody was home, she was surprised to find a birthday party for her, that Kouta, Nyu, and Yuka set up, with a birthday cake donated by the bread merchant. Breaking her vow never to cry again, she was soon to have one more piece of joy, as Wanta had followed her back to Maple House, which became their new home.
In the anime, these events ran a little differently. Police received word a girl was loitering on the beach (perhaps told by the woman who took Wanta), but the arriving Kouta and Yuka said she was family, and that there had been an argument. Mayu was still surprised by the cake and her birthday celebration, and Wanta returned shortly after that. In neither version is the actual reunion of Mayu and Wanta depicted, but it can easily be assumed to be a joyous one.
Life at Maple House
Despite reluctance on Mayu's part, Kouta and Yuka eventually did contact Mayu's mother. They were given practical custody of her without prompting or discussion, a fact the young couple found suspicious but did not pursue with Mayu.
Her guardians enrolled Mayu in a local school. She appears content and happy whenever she is in her school uniform and about to go to school, though she continues to worry about things, at one point being cautious while taking Wanta for a walk on the beach, fearing that his supposed former owner will return (She never does). One day places her new home and family in severe doubt. As Kouta bathes in the onsen, Nyu unexpectedly joins him, leaving Kouta flabbergasted and Mayu, dropping off clean towels, believing the worst of Kouta. In her mind, she was perhaps in the same trap again, even avoiding telling Yuka for fear of a similar reaction to that of her mother. Time seems to repair at least some of this, though Mayu developed a snarky streak when it comes to dealing with Kouta. While respectful, she would offer soft-spoken digs about bathing with Nyu or his denseness towards Yuka's feelings for him. After a certain point, she also ended up thinking all the adults in the house perverts through more misunderstandings about Nyu's over-enthusiastic antics. Though in one incident, Nyu's actions made it clear that she was out of control on all fronts, as when she squeezed one of Mayu's breasts, looking disappointed at her immature size. Later still, when Nyu had matured in personality, Mayu revealed her maturation by gently teasing Nyu about the incident.
Mayu contributed to Maple House through the assumption of some chores, but also with her hard-won savvy. This hard-won knowledge worked in particular when Kouta and Yuka found themselves tricked by the scheming Professor Kakuzawa into surrendering custody of Nyu, ironically claiming that she was his brother's daughter. Panicked with the Professor's fast talk and veiled or outright threats of prosecution for kidnapping, the two never raised the question that Mayu did almost instantly: was the Professor telling the truth about his relationship to Nyu? This correct notion set the pair on a journey that ultimately recovered Nyu, albeit one that settled some issues and raised a host of others, a recurring theme in all their young lives.
While the search for Nyu went on, one particular day, while walking on the beach before school, she met up with the soldier whose life she had once saved. Glad that he was alive, she expressed her happiness for his good health, with perhaps her forgetfulness about Nana's injuries making her not question Bando's recovery. Bando was surprised and upset that such a little girl saved him. Not wishing to be on her or anyone else's debt, he gave his cell-phone number to Mayu, in case she gets into trouble and needs help. Bando also told her to call him if she saw a horned woman. Mayu then asked if he was referring to Nyu, at which Bando immediately grabbed her and demanded to know if she knew Lucy, which Mayu claimed she didn't, lying about someone her brother met at college. Bando thought she was lying, and persisted in making threats, even to her life. Thinking quickly, Mayu showed him his phone number, saying that she's now in trouble. Disgusted with Mayu and with himself for caring about her at all, Bando released her and warned her not to let him see her again.
Shortly after Nyu's recovery, Mayu, once more taking a walk with Wanta, found Nana, who fought with Nyu in her "dream." Relieved to see her in one piece, Mayu again concluded that the fight was just a dream. When a nervous Nana dropped her prosthetic leg, Mayu fainted, and Nana takes her to a rest shelter in a nearby park.When Mayu woke, it was already night, and Nana introduced herself. Mayu asked what happened to Nana's leg, but before then noticed Nana's horns. Nana was afraid that Mayu hated her for them, but Mayu says she thinks they're cute, and begins to befriend her. Mayu came to understand that Nana was homeless like she once was, and knew nothing of the world, even burning the money her 'Papa' Kurama gave her to live, for warmth. Mayu again showed her snarky side when ferreting out information from Nana that confirmed her lack of knowledge about the world. When Mayu asked if Nana knew about Nyu, she decided to take a now-concerned Nana with her to Maple House. Surprised by a playful Nyu, Nana attacked her, thinking (for obvious reasons) that she was Lucy. Upset and offended by the rebukes the others, particularly Kouta and Mayu herself, gave after this assault, Nana fled, back to Jouju-in Cemetery in the manga, and to Michibiki Jizoudou shrine in the anime. In both instances, Mayu points out why the others were upset, and Nana first realizes the distinction the between Lucy and Nyu. With some reverse-psychology from Mayu, Yuka, and Kouta, and after some apologies and adjustments, Nana begins to settle in, helping some with the cooking and cleaning and eventually taking over the feeding of Wanta. Mayu remains at Maple House with Yuka while Nana, Lucy/Nyu, and Kouta are away during the events of the Mariko arc. In the anime, these events conclude the series, at which time Mayu openly proclaims Maple House to be her home, with Kouta and Yuka as parents to herself and Nyu and Nana, who she sees as sisters. Mayu is at the dinner table with the others offering prayers of thanks, just before an unexpected visitor concludes the series. In the manga, events pick up six months after Mariko's death, and Nana describes Mayu as still hopeful, and still not adept at dealing with guys, a lingering mistrust brought about by her stepfather's abuse. Unlike in the anime, she never declares Kouta and Yuka as her parents, though this is how she sees them. Mayu has been visiting Bando on the beach, where he prepared for the day of his rematch with Lucy. She brings food to both Bando and a man he is caring for, not realizing that the second man was, in fact, a mentally broken Doctor Kurama, who her 'sister' Nana considers to be her 'Papa.' Mayu still finds herself in the odd position of being the more mature of her sisters, even to the matured and Lucy-free Nyu, as when she if forced to restrict her to home due to Bando's presence on the beach.
Events began to wrap up the series and became very grim indeed. Mayu and Nana managed to survive the attack of the vicious Unknown Man. Every moment of the horrifying incident was a living nightmare for Mayu, as the mercenary pedophile severely injured Nana, seemed to kill Wanta (he survived) and threatened to rape and then disfigure Mayu when she resisted. At this moment, a horrid memory of her stepfather both froze Mayu and then drove her forward, giving her enough peace of mind to call Bando. As Unknown Man prepared to fire his crossbow directly into her face, Bando emerged and pounded on the attacker till he begged for mercy. Mayu herself halted Bando's effort to kill the lowlife, but Unknown Man fled nevertheless, overwhelmed, humiliated and just plain fearful. But as with many happy moments during the series, this one was destined not to last.
Bando prepared to leave and bury the remains of an unfortunate Diclonius killed by the Unknown Man. But at that moment, Kouta and Yuka returned from school and an encounter with the anxious Doctor Arakawa, with Nyu in tow, who Bando instantly recognized as Lucy. Even if he had targeted the peaceful persona, Bando's shooting of Nyu immediately awoke Lucy for the first time in several months. As the enemies prepared for a showdown, Bando made clear to Mayu his contempt and disdain, which she kept Nyu a secret from him all that time. As Kouta and Yuka tried to make sense of what happened to their home and family, Mayu fled to Yuigahama Beach, wishing to make amends with Bando, to whom she had grown very attached. Nana overcame her wounds and also went to the beach separately.
The second fight between Bando and Lucy went back and forth, with Bando's many traps and precautions at first playing greatly to his advantage. During the fight, Mayu attempted to make it clear to Bando how sorry she was, and how, despite all his seeming gruffness, she adored him. Bando did not push her off entirely, but also made it clear he was caught up in the fight. The interference of Unknown Man (whose odd tender worship of Lucy proved to be one-way and fatal) threw off the pace of battle. Nana (who was too weak from being attacked to make a real difference) and Mayu's apology/confession also combined with some of his tricks and traps being less dangerous than he'd hoped placed Bando once again in mortal peril, and cost him his other arm. The direct, indisputable sight of this maiming forced Mayu to accept that the girl she called Nyu was, in fact, a killer and monster like Nana had told her. Her secret in danger of being revealed to Kouta, almost on instinct and with some expressed regret, Lucy prepared to kill Mayu. Bando both leaped in the way of Lucy's deadly vectors and shot one of her power-enabling horns off, which caused Lucy to run off and revert to Nyu once again. But Bando had been split in two, and as he died, he let Mayu know it was his belief that no one would ever weep for him when his time came and was glad she was there to care that he ever lived. Mayu comforted Bando by lying and saying that Lucy was finally dead by his hands. Knowing that the battle would attract attention, Nana insisted that she and Mayu withdraw from the beach, where someone unknown but likely government forces collected Bando's body and all evidence he and Lucy had been there. In tribute to his memory, Mayu began to clean that beach every morning.
Back at the same rest shelter from earlier in the series, Nana explains her life and past to Mayu, including about Lucy, about which Mayu was still disbelieving, despite all she had seen. Mayu flatly stated she did not want to see Nana become a killer, even to stop as significant a threat as Lucy. The two also stopped the overhearing Nyu from either killing herself or being killed by Nana, when Nyu learned that she was also the killer, Lucy. Mayu had already made the suggestion several times, and when Kouta, guided by Wanta, came to fetch them all back, they left for home and dinner. At this dinner, Kouta had planned to at last press everyone for what they knew, but this was another idea soon to be made impossible.
After the dinner was done, and while waiting on school entrance results for the Maple House's newest resident, Nozomi, the housemates saw their home invaded. Mayu was among those terrified and helpless as forces loyal to Chief Kakuzawa invaded and assaulted Maple House, seeking to recapture Lucy and execute Nana. The soldiers involved brutally pushed the residents aside, with Nozomi and Kouta, in particular, injured in the attack. At seeing Kouta shot by the Agent who de facto led the force, Mayu was as horrified and concerned as anyone. At first, Nyu went wild, finally showing she could use powers as well, but when the fighting intensified, Lucy emerged, turning back the attackers, until captured herself. Before her leaving, she directed Yuka to care for Kouta and Nana to look after their family. If she had words of regret for attempting to kill Mayu, she did not express them here, and this would be the next to last time the two would ever see each other.
At the hospital, Mayu kept watch over Kouta, and to the extent, she could, Nozomi. After the attack, Nozomi's overprotective father was keeping her away from her friends. She seemed, along with Yuka, to be staying at the home of Yuka's mother while they began to reclaim Maple House from the damage of the attack. Unable to keep bringing food to Kurama (and still not knowing who he was), Mayu asked this of Nana, who was anxious to get away from an argument about whether she could still live at Maple House. Some days after he entered the hospital, Mayu lost track of Kouta, who it turned out had gone back to the beach, somehow sensing Lucy would return there. For the rest of the series, the focus of events split between efforts by Japan's Self-Defense Forces to deal with the threats posed by Lucy and the Kakuzawas, Lucy's showdown with the Chief, and Kouta settling past pains with Nyu, now that his memory had returned. Owing to this, Mayu and characters other than this appeared only briefly, wondering where the others were. One exception was Nana, who stayed by Kurama's side as his role in the finale played out.
All Maple House residents made it atop the remains of the Sea Candle, a lighthouse destroyed by Lucy's power as she raged over a dying Kouta, till she turned her energies instead towards saving his life, at the expense of her body's stability. When one last wave of soldiers came at them while Kouta considered a request to kill Lucy's body, Mayu again urged Nana not to become a killer, a position the vicious Diclonius DNA Voice within the former Lucy/Nyu's body was all too happy to occupy. Itself exhausted and in agony, Mayu and all the residents heard the Voice begging for merciful release from its pain. It was a release that a tearful and reluctant Kouta finally acquiesced. In the manga finale, Mayu is cleaning up both Maple House, prepping for the day of Kouta's release from the hospital, and the beach once used by Bando. Despite having been split in two by Lucy, Bando shows up alive, more machine than man now, but with each happy to see the other. It is possible that Mayu maintained romantic feelings for Bando, who does apparently care for her. The series ends before we learn whether these feelings ever came to anything. The two have a happy ending of sorts, with Mayu going from people who were far worse than they seemed (her parents) to individuals who were just what they seemed (Kouta and Yuka) and finally taking the risk to befriend Bando, who ends up being more than what he seemed. Also in the manga finale, when Wanta is wandering about town without his leash, Mayu is concerned but does not suffer the anxiety attacks that she would have earlier, and now has the optimism to believe he will return. In fact, he witnesses her reunion with Bando from a remove.
Presumably, Mayu acted as an older sister (Onee-Sama) figure to any children Kouta and Yuka had later on, and likely remained close to Nana. She does not appear again in the manga after her reunion with Bando.
Given the anime's time constraints, it may seem as if Mayu overcomes her problems and traumas rather quickly and thoroughly, even comfortably calling Kouta and Yuka her parents. The manga continues to show the after-effects of her abuse, including a period in which she did not trust Kouta, a description by Nana as to her being 'not good with guys,' and a violent, somewhat explicit flashback to her stepfather's rape during the attack of the vile Unknown Man. Fan speculation about her post-series fate has placed her romantically with Nana, Bando, and even Kouta.
- Mayu appears by herself on fourteen manga chapter covers, sometimes with Wanta. This amount ranks her fourth for all such appearances.
- In the anime, Mayu ends up learning the nature of Diclonius and Lucy well before any other Human resident of Maple House, and much earlier than she did in the manga.
- Mayu physically resembles Angela Orosco from Silent Hill 2 and may have been inspired by her. Both possess dark brown hair in a similar hairstyle, as well as matching sweaters. The two also share the unfortunate circumstances of being homeless teenage runaways who were sexually abused by their parents/stepparents. They also share androphobia (fear of men) that manifests in their reactions to actions by the male characters around them. Angela, for example, lashes out at James several times and claims men are "only after one thing"; Mayu behaves coldly toward Kouta for a time and panics during the Unknown Man's assault on her. Wanta is even called "James" by the woman who was supposedly his owner.
- Mayu makes an appearance on the back of the 2013 Blu-Ray release of Elfen Lied. On it, viewers see Mayu, Yuka, Shirakawa, and Arakawa in a choir like that of the choir of women from the Beethoven Frieze by Gustav Klimt, the art style reminiscent of the anime's opening credits.
- A special manga story set in the anime continuity reveals Mayu cannot swim. She also placed her shoes neatly by the shore, suggesting that she was possibly going to attempt suicide by drowning herself before Wanta ran up to her and got her attention. In Japanese culture, those committing suicide remove their shoes beforehand and place them close together.
- No one in either the anime or the manga ever directly learns of the abuse Mayu suffered in her original home.
- Mayu's backstory resembles that of Aoi Kurosaki from Devilman Lady. Like Mayu, Aoi had a sexually abusive step-father and a neglectful mother who hated Aoi out of jealousy for "stealing" the attention. However, unlike Mayu, Aoi is mentally twisted as a result of the abuse.