The pureblood vampire who bit Zero; even her fellow vampires are uneasy around her. She is called "Mad Blooming Princess" by her fellow vampires. A manservant whom she loved (a former human vampire; said to have never fallen to Level E) was killed by a Kiryu vampire hunter. In retribution, she attacked the Kiryu family, killed the parents, turned their son Zero into a vampire, and took Zero's twin, Ichiru, in as a devoted servant.
Shizuka's blood can prevent Zero from falling to Level E, and thus Yuuki risked her life for Zero to be able to drink Shizuka's blood. But Kaname killed Shizuka to protect Yuuki. Kaname drank her blood, but left some for Zero to drink as well. Unfortunately the blood was drunk by Ichiru who arrived at the scene first. Before dying, Shizuka warns Kaname that he will live in darkness and has summoned a sinister future for himself.