The first clip from DreamWorks Animation’s Riders of Berk is now online and can be viewed at ComingSoon.net. The site also reveals that the How to Train Your Dragon spin-off will debut on Cartoon Network on September 4th at 7:30 ET. In addition to featuring the characters from the film, the series will also introduce new worlds, new dragons, and Alvin the Treacherous, Hiccup’s arch-enemy who will be voiced by Mark Hamill.