TV-Series
Description
Mai Kawasumi is a third-year high school student who is one year senior to the protagonist, Yuichi Aizawa. She stands at 167 centimeters tall and has a slender build, with long, dark blue hair that she typically wears in a ponytail using a purple hair tie, and green eyes. Her most distinctive feature is the long sword she carries, which she brings with her to school.

She is a girl of very few words, having a quiet and introverted personality that makes her seem distant or unapproachable. This taciturn nature, combined with the injuries she sustains and the property damage caused by her nightly activities, has led many of her classmates to view her as a delinquent or problem student. She does not bother to correct these misconceptions or defend herself against accusations, knowing that the truth about the monsters she fights would not be believed. Despite her cold exterior, she possesses a gentle nature that is recognized by those closest to her, though she struggles to express her emotions openly. Her statements are often blunt and serious, and she has a peculiar habit of adding the honorific "san" to animal names when playing word games, a trait inherited from her mother.

Several years before the story begins, Mai possessed a remarkable and mysterious power: the ability to make her wishes come true through sheer strength of emotion. When her mother was critically ill and near death, the young Mai prayed fervently for her recovery, and her tears seemed to carry a miraculous healing ability that saved her mother's life. This event drew unwanted attention, and Mai was subjected to a witch hunt by the media and public, who labeled her a freak or a monster because of her powers. To escape this persecution, she and her mother moved to a new town, the setting of Kanon.

Approximately ten years prior to the main events, during a summer break, a young Yuichi met Mai in a golden barley field, and the two became close friends, spending two weeks together. When the time came for Yuichi to return home, a distraught Mai, unable to accept his departure, claimed that monsters had appeared in the field and that she needed his help to fight them. Yuichi was forced to leave regardless, promising to return one day. This event became the source of Mai's prolonged emotional struggle. Unable to let go of her feelings for Yuichi and her desire to keep their promise, her powerful wish manifested again, creating literal monsters from her own loneliness and pain. The barley field where they met was eventually torn down to make way for a new school, which is why the monsters began to appear there every night. For seven years, Mai waited for Yuichi, fighting these creatures alone.

In the present day, Yuichi discovers Mai late at night in their school, sword in hand, fighting these monsters, which she refers to as "demons". Her stated mission is to exterminate them. She knows from the moment of their reunion that Yuichi is the boy from her past, though she does not reveal this initially. As Yuichi becomes involved in her nightly battles, he also learns that Mai has one true friend: her classmate Sayuri Kurata. Sayuri is the only person besides Yuichi who understands Mai's true, gentle nature, and their bond is extremely important to Mai, who cherishes her deeply. Their friendship began when Mai protected a dog from danger, and Sayuri, instead of being afraid, shared her lunch with Mai. Mai is also perceptive regarding supernatural matters, being the first person to recognize the true nature of another character, Makoto Sawatari, and offering Yuichi guidance on how to help her.

A critical revelation occurs when Mai's best friend, Sayuri, is attacked and seriously injured by one of the monsters. The guilt and anguish Mai feels over this event cause her to spiral further into her struggle. The truth about the monsters is finally uncovered: they are not external enemies, but physical manifestations of Mai's own power, born from the pain of Yuichi's childhood departure and her years of lonely waiting. By fighting and destroying these monsters, she has unknowingly been harming parts of herself, which explains the strange marks and pain she experiences after each battle. In the climax of her story, upon learning this truth and blaming herself for the danger that befell Sayuri, Mai attempts to take her own life with her sword. However, in a final demonstration of her power, the last remnant of her ability, manifesting as the young girl she once was, saves her life and closes her wound. This manifestation, which Yuichi is asked to call "Hope," suggests that Mai can finally begin to accept her power and herself.

Mai's development throughout the narrative is a journey from painful self-deception and isolation toward self-acceptance and healing. Her desire to wait for Yuichi, while a testament to her loyalty, became a prison of her own making. By confronting the truth about the monsters being a part of her, she is able to let go of the past that was harming her and look toward the future. After recovering from her injuries, she resolves to become a veterinarian, showing a desire to care for living creatures rather than fight shadows. Her notable abilities include her wish-granting power, which is the source of both her childhood miracle and her later suffering. She is also a highly skilled swordswoman, possessing superhuman agility and strength that allow her to jump great distances, cut through solid objects, and battle the towering monsters effectively. Her fighting skills, however, are ultimately a means to an end, used for the self-destructive purpose of fighting her own inner demons made real.