As a mortal, Doug Sanders was a motivational speaker (and self-described 'life-coach.') He was involved in a pyramid scam or two, and was wanted by the police. It's at this time, he was turned into a vampire. As a vampire, he picked up right off where he left, but this time, his scams involved killing and siring humans. Angel and his team soon caught up with him, and his group, killing most of them, and decapitating Sanders.
Weird vampire. No clue why this guy was turned, but I guess it was probably by some unexperianced young vampires, or was created to be a mindless minion. If the latter is true, he had other plans, and decided to use what he learned as a mortal to pray on weak minded vampires, the same way he did things as a human. Of course, lacking a soul, he did a hell of a lot more evil.