The Empty Box and the Zeroth Maria

Utsuro no Hako to Zero no Maria (空ろの箱と零のマリア), also known as Hakomari (箱マリ) for short, is a Japanese light novel series written by Eiji Mikage, with illustrations by Tetsuo. The first volume was released on January 7, 2009. Currently, there are 6 published volumes published by ASCII Media Works under their Dengeki Bunko label.

Plot Synopsis
Utsuro no Hako to Zero no Maria, or The Empty Box and The Zeroth Maria, tells the story of Kazuki Hoshino, who is almost madly attached to his everyday life, and his antagonist Aya Otonashi, who suddenly transfers into his class at the end of the school year—for no less than the 13,118th time. Without hesitation, she announces her intent to “break” him. Kazuki's struggle to defend his everyday life begins, and the many secrets it is built on start to come to light.

Volume 1

Kazuki Hoshino, a teenager in high school, cherishes the "everyday life" he shares with his friends Haruaki Usui, Kokone Kirino, and Daiya Oomine, as well as his crush, Kasumi Mogi. This normalcy is shattered, however, by the sudden appearance of a mysterious female student who transfers to his school in the middle of the year--a change that Kazuki is inexplicably already aware of. After introducing herself as "Aya Otonashi," the girl interrupts the class abruptly and orders everyone to write her name on a piece of paper. When Kazuki writes the name "Maria" on a whim, Aya, surprised and angered, accuses him of toying with her and drags him out of the classroom.

She explains to Kazuki that she, he, and the other students are trapped in an alternate reality she calls the "Rejecting Classroom" where the same day, March 2nd, repeats indefinitely; she has already transferred to Kazuki's class 2,601 times. By writing the name "Maria," which Aya used on her first transfer, Kazuki has unknowingly revealed that he can remember previous iterations, an ability which only Maria and one other person, the owner of the wish-granting "box" that created the "Rejecting Classroom," should have. Aya's goal is to identify the owner and obtain the "box," but she has failed countless times, resorting to the name-writing ploy out of desperation. Enraged that Kazuki has risen to such bait after thwarting all her genuine plans, Aya accuses Kazuki of being the owner and orders him to give the "box" to her. When Kazuki explains that he does not know how to, Aya resolves to pursue him relentlessly until he does and also reveals that the "Rejecting Classroom" can end another way--through the death of the "box's" owner.

Main characters
Kazuki Hoshino (星野 一輝): Kazuki is the protagonist of the Hakomari series. He is a completely ordinary high school student who loves idle chatter with his friends and Umaibōs, a Japanese snack. The story begins when Kazuki is offered a box by O. Kazuki however refuses the box because the only thing that he wishes for is a normal everyday life. Because of Kazuki's disinterest in the box and his will for an everyday life, O becomes interested in Kazuki. O gives boxes to several people around Kazuki, and before Kazuki knows it his everyday is being destroyed in several different ways. O makes it his mission to study Kazuki in these different scenarios until he believes Kazuki will give in and use a box himself. One day, he is suddenly antagonized by Aya Otonashi — although he has never met her before. She threatens to "break" him.

Maria "Aya" Otonashi (音無 麻理亜): Maria is a beautiful but unsociable girl with a resolute personality. She transferred into Kazuki's class on March 2nd — almost at the end of the school year. Maria is very stern in her actions and beliefs. She expressed her wish to "break" Hoshino at the very beginning. There is one however one thing that Maria is terrified of, and that is killing someone else. No matter the circumstance, Maria refuses to kill anyone even if it meant saving Kazuki's life. Maria cares deeply for other people because of her wish to become a box herself and is willing to sacrifice her own memories in order to give other people a place where they can be happy inside her box.

Supporting characters
O: 'O' (not to be confused with the numeral 0, "zero") is the main antagonist of the series and the giver of the wish-granting boxes. Throughout the series, 'O' demonstrates a fascination with Kazuki Hoshino (who rejected her offer of a box before the events of the story) that motivates her to alter and observe Kazuki's life by giving boxes to the people around him. A supernatural entity whose appearance constantly changes, 'O' describes herself as a "vector," a form and purpose that was given to a much larger, transcendent but ultimately purposeless being with the ability to grant wishes. Daiya Oomine later realizes that 'O' was created as a result of Maria Otonashi's initial wish that became The Flawed Bliss, with Kazuki Hoshino serving as 'O's counterpart, The Empty Box. At the start of the series, 'O' considers Kazuki to be very dear, but after coming to the realization of her origins, 'O' takes on the appearance of Maria's deceased older sister and declares Kazuki to be her enemy. Calculating and emotionless, 'O's one ultimate motivation seems to be the observation of interesting humans and the "groaning of their hearts."

Kokone Kirino (桐野 心音): Kokone is a bright and beautiful girl who cares a lot for her friends, but is meddlesome at times. She and Daiya have known each other since childhood, and their mutual verbal abuse has become legendary among their classmates ever since. Kokone is a very outgoing person. She likes to tease Kazuki, Haruaki and Daiya, who often tease her back.

Daiya Oomine (大嶺 醍哉): A self-centered and arrogant student who dyes his hair silver and wears three piercings in his right ear. He is the class president of the second year students and a shrewd friend of Kazuki's.

Kasumi Mogi (茂木 霞): Kasumi is the girl who has won Kazuki's heart. She is docile, silent and expressionless. Kasumi lived a normal life going to school, however she was always depressed. Since she never showed any emotions herself, always forcing a smile onto her face, and was never happy, she thought everyone else must be faking it too. She thought nobody would ever notice her, until one day Kazuki ran towards her after she left school asking if she was okay, because she seemed bothered. Mogi denied having anything bothering her, but at the same time she fell in love with Kazuki as he noticed that her smile was fake.

Haruaki Usui (臼井 陽明): Haruaki is a cheerful but frivolous baseball ace. He often hangs out with Kazuki and Daiya.