Half Bloods are individuals with unpure linneage, usually born from a Vampire/Demon and Angel, but occasionally from a Vampire/Demon and Human in Nao's case.  At birth, all Half Bloods, also known as Mixed Bloods, are given a curse brand on their chest; if they don't drinkt he blood of a full fledged demon before they turn 18, then the curse will kill them by corroding away at them. 

Known Half BloodsEdit

Name Linneage
Tsukimiya Vampire/Angel
Hinata Vampire/Angel
Nao Vampire/Human