Demon Lords

Demon Lords are fallen True Ancestors who succumbed to their blood thirst and became a threat both to humans and the Ancestors themselves. As they no longer needed to suppress their thirst, they could employ their powers to their full extent and therefore vastly overwhelm their still restrained kin. It was with the purpose of their elimination that the Ancestors caused the birth of Arcueid Brunestud. By the time of Tsukihime, all of them had long been eliminated. It should be noted that despite the name, they are not to be confused neither with the demonic ethereal beings born from human belief, nor with the oriental demons of Japanese folklore known as Oni.