In the novel, Kaori is a young girl whose father owns the abandonded lot where Mitsuru discovers the portal to Vision. After an attack by local teenagers, in which she was heavily implied to be raped, Kaori was left in a vegetative state.
Near the end of his journeys in Vision, Wataru discovers her soul in the form of a bird mysteriously trapped there. Upon freeing it, Kaori is able to once again speak and walk.
Brave Story (Manga)Edit
In the manga, Kaori is a 14-year old girl who is the same age as Wataru. Her father once again owns the abandoned lot that contains the portal, but her tragic backstory doesn't exist in this continuity. Instead, Wataru initially meets her on the property and becomes smitten with her.
Later, Kaori becomes a Traveler herself after following Wataru into vision. Kaori becomes a Cannoneer using equipment from Wayfarer Lau. Her reason for entering Vision is that her family is poor because her father was never able to finish the expensive building construction, driving them to the brink of poverty. As a result, her father became suicidally depressed, which gave Kaori the sense of desperation that allowed her to become a Traveler.