Aoi Misato is a central character who serves as the respected student council president at Magami High School in Tokyo. She comes from a wealthy and traditional family and is widely liked by her peers, maintaining a particularly close friendship with Komaki Sakurai. Physically, she is a beautiful young woman with gray eyes and long gray hair that reaches her waist, and her birthday is September 20.

In terms of personality, Aoi is characterized by her profound sensitivity and compassion. She is described as being sweet to the point of naivety, and she becomes genuinely distressed whenever someone is in trouble or hurt, as she inherently believes there is good in all people. This gentle and kind temperament, however, creates a significant internal struggle when she is forced to confront violence, as her desire to protect others can become an obsession. Her defining motivation stems from a traumatic childhood memory where she was unable to save a friend from dying in a fire. Trapped herself beneath burning rubble, she survived but carries a physical scar down her back, which she refers to as her stigma. She is deeply ashamed of this mark and only reveals it to Tatsuma Hiyuu during a moment of vulnerability, after he shares his own story and shows her his birthmarks.

Within the narrative, Aoi is considered the physically weakest member of the Magami team during their battles to protect Tokyo from supernatural threats. Because of this, her friends, particularly Kyouichi Houraiji, are constantly looking out for her, often forcing her to stand down for her own safety. Despite his rude and cruel tone, Aoi is never truly troubled by Kyouichi's demeanor and attempts to defend herself, and there are subtle indications of mutual romantic feelings between them. She also shares a deep bond with Tatsuma Hiyuu, as they possess nearly identical personality traits. Tatsuma is often the one who speaks candidly with her without judgment, and she appears to have strong feelings for him as well, even calling out his name at graduation. Another key relationship involves Hisui Kisaragi, whose family has had long-standing business dealings with the Misato family. Hisui has been close to Aoi since childhood, drawn to her warmth and sincerity, and he remains deeply loyal to her even as he struggles with the duty of his clan.

Throughout the story, Aoi undergoes significant development as she grapples with her inherited destiny. She is born under the Yata star, and her Shukusei, or Star of Fate, is represented by the Yata-no-kagami, the Eight Hand Mirror, which is an object symbolizing wisdom and honesty. Further burdening her fate, Aoi discovers that she possesses the Bosatsu-gan, or Bodhisattva Eye. This incredible power grants her the ability to heal others and even resurrect the dead, but it comes with a dangerous cost. The Bodhisattva Eye functions by drawing the physical energy from the person being healed, and if too much energy is drained, it can kill them by effectively aging them to death. This dual nature gives it the potential to save anyone or kill everyone, making it a highly sought-after and feared power that brings conflict and potential destruction. Her role as a healer and her possession of this eye are central to the plot, as enemies seek to control this power while others are sworn to destroy it.