Michael Roa Valdamjong is the main antagonist of the Near-Side Moon routes of Tsukihime. He is a vampire and a numberless Dead Apostle Ancestor ranked as “Extra” outside of the regular twenty-seven because they consider him to be a heretic who does not uphold the ideals of regular vampires.
Michael Roa Valdamjong is the unofficial twenty eighth of The Twenty-seven Dead Apostle Ancestors in the Tsukihime Remake series. Former priest of the Holy Church. He is called The Serpent of Akasha and The Infinite Reincarnator, which refers to his ability to constantly reincarnate after entering Akasha, the root of everything within the universe, no matter how many times he dies. His seventeenth incarnation is known as Elesia, and his eighteenth incarnation, SHIKI Tohno, is his latest as of the time period of Tsukihime.
Here is his character description, via the game’s official website:
A vampire seen known as the “Serpent of Akasha” or the “Infinite Reincarnator.” Former priest of the Holy Church. He can manipulate information and electricity at will. The story of Roa appearing in Souya that came to him predicts the possibilities he might have had following a chance encounter with Arcueid and Shiki.
This character is a main antagonist of the series as he has an unhealthy obsession to one of the main heroines of the game namely Arcueid Brunestud. Ever since he became a vampire and rose in the ranks, he used all of his reincarnations to seek and try to kill Arcueid Brunestud. Throughout centuries and sixteen reincarnations, he has tried and lost to Arcueid Brunestud.
The seventeenth marriage that Roa mentions to Arcueid early in the fight doesn’t mean he has sixteen other wives elsewhere but this is the seventeenth time that he’ll attempt to kill her this time. In the story, Arcueid, Shiki Tohno and Ciel work together to take down powerful vampires that show up in Misaki Town where the whole Melty Blood series is set in.