True Ancestor
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True Ancestors (真祖 shinso) are unique amongst the blood-sucking species; they have always been vampires. They are nature spirits that are the closest to elementals. Their purpose is to return the planet to its original state.
[edit] Nature
They aren't divine spirits since they aren't affected by the conception humans have of them. As they are a species of nature spirits, the beast of Alaya doesn't target them for destruction even though they are hostile to humanity. They are mediator of nature before being enemies of humanity.
True Ancestors with a female body are rare, probably because the original Crimson Moon had a male body. They are creatures that were desired by the world but not by humans, so they gradually went underground, and their number decreased. By the time Arcueid Brunestud was born in the 12th century, their number had gone down to a hundred heads.
As they are part of nature, they can change the world with Marble Phantasm at will. As candidates to the succession of the Crimson Moon, they are nature spirits that were born without the nature's sense of need for protection from humans. When a successor of the Crimson Moon close enough to him will be born, the Crimson Moon will take possession of him. For that reason, True Ancestors all have a part that can receive him inside them.
[edit] Origin
The True Ancestors are born from nature and the Reality Marble left by the Crimson Moon. The structure of their soul and body was created based on humans who are their targets, but as the reference was the Crimson Moon, they bear the fatal flaw that is their vampiric impulse. They have the power to transform the world by just willing it, but they need channel all their power of thought to restrain the vampiric impulse, hence they are never able to use 100% of their power.
To be at their very best, they need to sleep through childhood. If they can't solve their vampiric impulse and the lust accumulates, when they cannot bear the bloodlust anymore, they are put into eternal sleep, as true Ancestors do not have a finished life span.
True Ancestors who succumb to the vampiric impulse are called "fallen True Ancestors" or "demon lords", and suck blood without discrimination. As fallen True Ancestors don't need to restrain their bloodlust, ordinary True Ancestors cannot stand up to them.
Arcueid Brunestud was originally created with the purpose of killing fallen True Ancestors.
They were all born with the purpose of being the successor to the Crimson Moon, yet they always bore the fabrication default; when the Crimson Moon understood that, the other True Ancestors arranged for a new one to be born with that purpose. Originally, it is a phenomenon generated when needed; but Arcueid Brunestud was created from nothing with the intention of making her perfect.
There has been only one occurence of a child being born from a True Ancestor and a human.
They don't dream, but in Arcueid's case, she must dream a little since her meeting with Tohno Shiki.
Source: based on the Tsukihime Dokuhon PlusPeriod dictionary entry (p.183) and the dictionary resource at Jonnobi.
