Arashi Kishu is a sixteen-year-old girl who serves as one of the seven Dragons of Heaven, also known as the Seven Seals, fighting to protect humanity from the destruction sought by the Dragons of Earth. Her name carries the meaning of "storm" or "demonic storm". Known as the hidden shrine maiden of the Ise Shrine, she is considered one of the most sacred figures in Japan and is typically only permitted to leave the shrine in cases of extreme emergency.

Arashi's origins are marked by tragedy. Her mother was a shrine maiden at the Ise Shrine who fled upon discovering that her unborn child was destined to become a Dragon of Heaven, hoping to spare Arashi from that fate. After her mother died when Arashi was seven years old, the young girl was left alone and lived on the streets, surviving on garbage and struggling with whether her solitary existence held any meaning. She was discovered outside the Ise Shrine by Kaede, the shrine's high priestess, who convinced Arashi to continue living. Kaede spoke to her of the future, explaining that Arashi would grow up to become one of the seven seals and would meet people who would care for her, even someone who would fall in love with her. Kaede also expressed that she herself would be sad if Arashi died, which ultimately moved the girl to accept her life and begin eating again. From that time forward, despite Arashi's outward coldness, a mother-daughter relationship formed between them.

In terms of personality, Arashi presents herself as a remarkably beautiful but serene and distant young woman who rarely loses her composure. She is taciturn, stoic, and keeps to herself, displaying little emotion even in difficult situations. Her tragic childhood forged in her a character that is both tragic and aloof. She is not skilled at socializing with others, sharing a similar disposition to Kamui in this regard. However, beneath her cold exterior, she possesses a genuine kindness and does show concern for others on occasion. She finds it difficult to outwardly express her feelings, but her interior world is more complex than her impassive face suggests.

Arashi's primary motivation throughout the story is to fulfill her duty as one of the seven seals and to protect Kamui, the person who holds the power to change humanity's destiny. She is summoned to Tokyo by the clairvoyant Hinoto after Kamui returns to the city, and she is tasked with watching over him and confirming his identity. As the story progresses, her relationship with Sorata Arisugawa becomes a powerful motivating force. Initially annoyed by his persistent advances, she eventually comes to reciprocate his feelings, and her desire to protect him from a prophecy that he will die defending the woman he loves drives significant actions in various adaptations.

In the story, Arashi acts as a guardian and observer. She is sent alongside Daisuke Saiki to monitor Kamui, and she later receives a telepathic request from Hinoto to protect him. She moves instantly through space, demonstrating her ability to transport herself and others to different locations. Throughout her mission, she encounters other Dragons of Heaven, including Sorata Arisugawa, who immediately declares that she is the woman for whom he is destined to give his life. She also meets Yuzuriha Nekoi, a younger shrine maiden from Mitsumine Shrine, with whom she develops a friendship. Her role involves confronting illusions created by the Sakurazukamori, participating in the sealing of the sacred sword, and ultimately facing the emotional consequences of her powers being tied to her chastity.

The most significant relationship in Arashi's life is with Sorata Arisugawa. He falls in love with her almost immediately and proceeds to shower her with attention and affection throughout the series. At first, Arashi treats him coolly and is bothered by his flirtations, but she gradually begins to show signs that his attention affects her. Over time, she falls in love with him as well, though she struggles to express it. Sorata's childhood prophecy, which foretold that he would die protecting the woman he loves, weighs heavily on Arashi once she acknowledges her feelings for him. In the manga, after Sorata is injured saving her life, they confess their love and consummate their relationship, an act that causes Arashi to lose her powers as a shrine maiden.

Arashi's character development centers on her gradual emotional awakening. She begins as a girl who was once so detached from life that she considered starving herself to death, having lost the will to live. Through Kaede's kindness, she learns that she has the right to love and be loved. Later, through her interactions with Sorata and her growing circle of allies including Yuzuriha, she rediscovers the beauty of living and her character softens. Her cold exterior slowly gives way to reveal genuine care and concern, even as she struggles to express these feelings openly. Her journey involves moving from passive acceptance of her fate to active, emotionally-driven choices, even if those choices lead to tragic outcomes.

Arashi possesses several notable abilities stemming from her role as the hidden shrine maiden of Ise. Her primary weapon is an extremely powerful sacred sword that emerges from her left hand, which is described as the body of a god with Arashi herself serving as its sheath. She can use this saber to fight off enemies, including other powerful beings. She also has the ability to create a kekkai, a kind of barrier or sacred space, which takes the shape of a four-sided pyramid. Additionally, she can discover and identify shikigami, which are powerful spells that take human form. A crucial limitation to her powers is that her abilities as a shrine maiden, specifically her capacity to summon the sword, are tied to her virginity. If she loses her virginity, she loses these powers, just as her mother did before her. This creates a significant conflict when she develops a romantic relationship with Sorata.