Black Blood

Black Blood (黒血, Kokketsu) is a unique substance created by Azazel, after decades of research on the biology of Demons. Due to its unique existence, it isn't classified as Magic or a Curse, and remains "unclassified", as a result.

Trivia

 * The Black Blood is heavily inspired by the Black Blood within the Soul Eater series, with several differences to differentiate between them.
 * The Black Blood is used solely by the author, and friends of his for story-only purposes. Hence, no other user can use the Black Blood.