|Relatives:||Mother (abandoned custody)|
| Character Information
|First seen:||Manga: Chapter 7|
Anime: Episode 2
|Last seen:||Manga: Chapter 107|
Anime: Episode 13
|Voice actor (Japanese):||Emiko Hagiwara|
|Voice actor (English):||Cynthia Martinez|
|“||This place...It's the only place I've ever called home.||”|
–Mayu, in the twelfth anime episode
Nothing is known about the fate of Mayu's true father. At some point, her mother became disinterested, and detached from concerns about her daughter, though Mayu either did not realize this or did not realize the depth and breadth of the disconnect, which either always was or eventually became total. Her mother married a man she referred to as a 'new papa', indicating that the original 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 a period of 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, only to find homelessness almost as great a problem. She was forced to survive on bread crumbs and whatever she might be able to find. Lonely and depressed (possibly suicidal), she found a puppy and called him Wanta, even giving him food at her own expense, and stayed in a wood-pile shelter on the beach in Kamakura. While a hungry existence, the pair found it bearable so long as they had each other.
One rainy night, Mayu awoke to the sound of gunshots and screams on the beach. When she arrived at the source of the noises, she found a wounded soldier with his eyes bleeding and his arm cut off, in shock and agony. Calming him down, Mayu tied off his severed arm and called for an ambulance to come and get him. She also finds 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. Kouta realized that she witnessed what happened on the beach, and asked her to answer some questions, since he, Yuka and Nyu were attacked at that same time. Mayu is unable to answer most of his questions, and when Kouta asks for information about how she can be contacted, a nervous Mayu runs off, concerning Kouta and Yuka.
Soon after, she witnessed Nana's dismembering by Lucy, who also knocked her unconscious. She would later dismiss all this as a dream, repressing the memory. Because of the blow, she was taken 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 remembered what happened with Lucy and Nana, but again chose to believe it was a dream. When they asked if she had run away from home, Mayu again left, refusing to answer.
Completely devastated, Mayu made an effort to not cry. She suddenly remembered it was the last day the Bakery Merchant would be there, and decided to go 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 about her, when they came there looking for her. She 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 cake donated by the bread merchant. Breaking her vow to never 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 had been told of a girl 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 thereafter. 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
Mayu is enrolled 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. She also ends up thinking all the adults in the house are perverted through misunderstandings about Nyu's over-enthusiastic antics.
One particular day, while walking on the beach before school, she met up with the wounded soldier she had once saved. Glad that he was alive, she expresses her happiness for his good health. Bando is surprised and upset that he was saved by such a little girl. Not wishing to be in her or anyone's debt, he gives his phone number to Mayu, in case some day she gets into trouble. He also tells her to call him in case she sees a horned woman. Mayu then asks if he is referring to Nyu, at which Bando immediately grabs her and asks if she knows Lucy, which Mayu says she doesn't. Bando thinks she is lying, persisting in making threats. Until Mayu shows him his own phone number, saying that she's now in trouble. Bando releases her and warns not to let him see her again.
Mayu, once more taking a walk with Wanta, finds Nana, who fought with Nyu in her "dream". Relieved to see her in one piece, Mayu again concluded that the fight was a dream. When a nervous Nana drops her prosthetic leg, Mayu faints, and Nana takes her to a rest shelter in a nearby park.
When Mayu wakes, it's already night, and Nana introduces herself. Mayu asked what happened to her leg, but before her question was answered, she noticed Nana's horns. Nana thinks they were bother Mayu, but Mayu says she thinks they're cute, and begins to befriend her. Mayu understands Nana is homeless like she was, and understands nothing of the world, burning the money Kurama gave her for warmth. When Mayu asks if Nana is connected to Nyu, she takes a now-concerned Nana with her to Maple House, where Nana attacks Nyu, thinking she is Lucy. After some apologies and adjustments and with much help and guidance from Mayu, Nana begins to settle in, helping some with the cooking and cleaning and eventually taking over the feeding of Wanta.
She manages to survive the attack of the vicious Unknown Man by calling on Bando, who also saves her from Lucy's wrath, seemingly at the cost of his own life. Despite some ups and downs in their odd relationship, Mayu admits she adores Bando, and he in turn is glad to have someone mourn him, which he thought would never happen.
Mayu says in the last few episodes of the anime that Kouta is like the father and Yuka is like the mother to her. In the manga, while clearly respecting and caring for Kouta and Yuka, she never calls them by parental titles, possibly due to her poor relationship with her mother and stepfather
She is also among those assaulted when forces loyal to Chief Kakuzawa invade and assault Maple House. She and Nana become sisters, each helping the other when they wish to run away at various points. Nana observes later on in the manga that Mayu is still nervous around guys, even Kouta, though her feelings for him seem entirely positive. No one in either the anime or the manga ever directly learns of the abuse Mayu suffered in her original home.
In the manga finale, Mayu is cleaning the beach once used by Bando, who, despite having been split in two by Lucy, shows up alive with each happy to see the other. It is possible that Mayu maintains romantic feelings for Bando, who does apparently care for her. Whether these feelings were ever acted on is not revealed, but the two have a happy ending of sorts, with Mayu going from people who were not what they seemed (her parents) to people who were exactly what they seemed (Kouta and Yuka) and finally taking the risk to befriend Bando, who ends up being more than what he seemed. It is worth noting that, 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, and in fact he witnesses her reunion with Bando from a remove.
Presumably, Mayu acted as an older sister figure to any children Kouta and Yuka had later on, and likely remained close to Nana.
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 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.