Jason Dark

Helmut Rellergerd, known by the pen name Jason Dark, is a prolific author of horror detective fiction in the German language. He is known for creating the long-running dime novel series Geisterjäger John Sinclair, which has been ongoing since 1973 and is released weekly since 1978. As of 2020, the John Sinclair series sold more than 250 million novel copies and over 5 million audio drama units.
His work has been favourably compared to that of Sir Arthur Conan Doyle. Jason Dark is one of the most read authors in Germany in his genre.