Mithra is the true antagonist of the Syndrome series, causing the syndromes that affected the characters through out the series. In the appearance of a young child with gray hair, Mithra is very violent, being responsible for the deaths of Yukari, Arisa Kahara, Chisato and Mika Kishi. He is killed by Ryo Kazan, whom wields a katana to tear him apart in the conclusion of the story, apparently bringing an end to the syndrome.
Mithra also appears in a single scene in killer7 in the Alter Ego chapter, referred to as "The Oracle" in Hand in killer7. His reason for being there is unknown, though it may be connected to the full moon appearing at the beginning of each mission, connecting the game into the same universe. As The Oracle, he appears as twins who have the voice of an old man.
Mithra is the Zoroastrian god of contract.