Universal Pictures has set Peter Berg to direct “Bran Mak Morn,” an adaptation of the Robert E. Howard fantasy that Working Title Films partners Eric Fellner and Tim Bevan are mounting as an epic. Howard is the creator of muscular period fantasy novels and comics that include Conan the Barbarian and King Kull. Though lesser known than those two and title-challenged, “Bran Mak Morn” is comparable in scope. The adventure mixes the historical with the fantastical as the title character, a mythical king of ancient Britain, forges an alliance with supernatural troops to contest the unstoppable forces of the Roman Empire. The movie is the first fantasy foray for Berg, who last directed “Friday Night Lights.” “I’ve always been a big fan of action fantasy, loved ‘Conan’ as a kid and had been looking for something with that kind of scope and muscularity,” Berg said.