VAMPIRE

① Refers to a living dead that has regained its ego and self-awareness over time (regained the knowledge and wisdom it had when human).
② The probability of a living dead successfully becoming a vampire is about 1 in 10,000.
③ A vampire whose actions created a living dead, which then successfully became a vampire in turn, is referred to as a Dead Apostle.
④ There have been instances in which a vampires killed their Dead Apostle progenitor, thereby becoming a new Dead Apostle themselves.

Colorful MOON Tsukihime: Tsukihime Glossary