Appearing as a puppet maker, Touko is actually an extremely powerful sorceress.
Aozaki Touko appeared initially as the sister of Aozaki Aoko in the publicly unreleased novel Mahou Tsukai no Yoru, and made an later appearance in Kara no Kyoukai. In the animated movies of Kara no Kyoukai, she is voiced by Honda Takano, while Inoue Kikuko lent her her voice for the drama CDs.
In Kara no Kyoukai, she is shown as a puppet maker and as a occasionally designer of buildings. Together with Kokutou Mikiya, she runs a kind of detective agency (Garan no Dō (伽藍の洞, Garan no Dō?)) that only engages in cases with supernatural or abnormal elements. Touko does not share a particularly good relationship with her sister yet the causes for this break are unknown.
She's a powerful Magus, and she's able to reproduce parts of a body that can be used instead of the lost part. While this would be nothing special, she can reproduce the part in such a perfect way that it comes close to the real one. The glasses Tohno Shiki wears were originally made by Touko. Her sister Aoko stole them from Touko and made them indestructible.
As a doll-maker, she received a Sealing Designation for creating a doll (body) that was an exact replica of her own body.
Touko has 20 Magic Circuits, which was a surprise to the Aozaki clan as the number of Magic Circuits in their line had been dwindling. Due to her formidable power, Mage's Association dubbed her with the color Tou (橙, Orange), which is close to the three primary colors. She wished to get the color Blue, but that title was taken by her sister Aoko.