Ryougi Shiki (両儀式) is one of the main protagonists of the Kara no Kyoukai novels. She is a teenage girl who possesses the "Mystic Eyes of Death Perception", a supernatural ability that allows the user to see the inherent mortality of everything (both living and non-living) in the form of lines.
She has short brown hair and brown eyes. She is usually seen wearing a red leather jacket over a blue kimono. When she uses her powers, her eyes glow an iridescent blue.
During the Fate/Grand Order collaboration event with Kara no Kyoukai, she can be acquired as an Assassin-class Servant.
Her third personality (aka the embodiment of the Void) can also be summoned as a Saber-class Servant. This version of hers wields the Kanesada Kuji, and as she gains power, her hair grows out, her kimono grows more elaborate, and has the Mystic Eyes of Death Perception activated permanently.