 Dave Thomas began his career in 1983 when he started producing multiple games for the Atari 400, including moderate-sellers such as "Warlok", which later won him in a competition from Calisto Software.Although he began working for the company in producing video games, he later quit due to the strain of his daily, commute.Shortly after quitting Calisto Software, Dave Thomas started work on "The Staff of Karnath", the first instalment of what would become the "Pendragon" series.