Niklaus (Klaus) was the youngest of four children. His life was a living hell from the age of three: his father and mother were members of the Cult of Revelations, and gave him and his oldest sister to the cult for experiments in pain, fear, and hatred as sources of power for magical workings. After five years of torture, he was thrown out on the street because he had outlived his usefulness. From eight until fourteen he worked as a child prostitute. One night, Klaus refused to submit to a rather obscene act. His john beat him severely, screaming obscenities, until something inside of Klaus snapped, and the next thing he knew he was covered in the man’s blood, his hands slowing shifting back into their natural shape from the talons that they had become.
Klaus ran, and didn’t stop running until he stumbled into an open sewer grate. He lay in the sewer, unconscious, and was found by a Pariah, who recognized Klaus as kindred and took him in. Klaus and his mentor later came to the United States, and acquired citizenship. In the States, he developed an intense love of philosophy, and discovered that he had a natural flair for languages.

For several years Klaus made a living as a social worker. Then came the night of fire, when the Sentinels swept through his small New England town, murdering Gifted. Many Pariahs died that night, among them Klaus’s mentor, and Klaus was left alone again. He fled to New Haven, remembering a kindly woman named Michele who was a friend of his mentor. Michele took him in, and introduced him to the rest of the group, who were in need of someone with his skill for linguistics. Anita Blake offered Klaus a room in her home upon returning to Pittsburgh.

After the conclusion of the original Nocturnum campaign, Klaus left Pittsburgh and traveled to a monastery in Tibet, hoping to make peace with his demons.