Rolf Muller was a human criminal. Because of the quarantine of Earth after the attack on Earth by the Drakh, Cynthia Allen's business dried up. She was unable to get a loan to keep her business afloat, so she went to Muller to get some money. She took 50,000 credits from Rolf Muller with 100% interest compounded every 6 months. After she made the deal with Muller, she was followed by him wherever she went.