Opposed to Tsukihime’s Shiki who is outgoing and thoughtful, Kara no
Kyokai’s Ryogi Shiki is cold and tends to keep to herself. The Ryogi
family attempted to create Human beings that exceeded normal Humans,
and to accomplish this, they trained their children in various martial
arts and fencing, and also made them split their personalities. They
believed that by using this method, one personality could be an expert
in one subject while the other could be master other subjects. Shiki
was no exception to this, and she had a masculine and feminine side
that switched places with each other (ref: Moonlit World).
A car accident causes Shiki to fall into a deep coma, and when she
awoke from it, she had gained the “Eyes of Death Perception” ability,
although she believed that her masculine personality side had died
during the accident. For those unfamiliar with the Type-Moon world,
users of the Eyes of Death Perception are able to see the “lines of
deaths” on every object that has a concept of death. By cutting these
lines, the user is able to perform extrodinary feats such as breaking
down a stone wall with a mere knife. When used on a living creature,
the user is able to sever nerves and limbs easily by cutting the lines
of his target. More experienced and skilled users such as Nanaya can
also see the “dot” of death on their target, and by piercing this dot,
the user can permanently erase something’s actual existance.