Second oldest to Non, Dreyfuss became undead in the early part of the 20th Century. After years of self-imposed isolation, he emerged as a soldier of fortune, hiring out his skills mostly to Third World countries, with little regard for his employers' moral stance. He never revealed to them what he was, they knew him only as an efficient covert leader and killer. It was in this capacity that he crossed paths with Non several times and was eventually persuaded, in the 1970s, to join the DC.
Of the Commandos, Dreyfuss is the most resigned to what he is. He wastes no energy debating the morality of killing to live; he cares little about what's behind the missions the DC are sent on, and he is disgusted by Non's insistence upon a spiritual life.