Michael Roa Valdamjong

A numberless Dead Apostle that Arcueid is searching for. He was a priest who sought immortality and was able to obtain it through reincarnation.

Spoiler

He tricked Arcueid into drinking his blood, therefore making him a vampire.

He is an antagonist in most routes of the game. Roa was taught a Reality Marble known as "The Soil of Genesis" which can only be destroyed with something that has a destructive power of something that can destroy a continent. It functions as some kind of cage or restraining device.
His original body was finally defeated by a coalition composed of Arcueid and the Church's Burial Agency, and he has been re-incarnating ever since then. By the time of Tsukihime he had already re-incarnated seventeen times and had been destroyed by Arcueid each time as she seeks to gain her stolen power back, and perhaps to achieve some measure of revenge. Roa has two requirements for choosing the host of his next reincarnation: the host's family must have a high social standing so that he would be born into luxury, and a body with high magical potential and perhaps unique latent powers.

Spoiler

His last host was Ciel, who was chosen in haste and thus was born into a bakery's family but in exchange had a body with an extremely high magical potential that was relatively close to that of his original form.

In Tsukihime, Roa is responsible for the grisly vampire murders throughout the city.