How did a line of toys inspired by a blood-soaked sexed up R-rated movie evolve into a quirky, nonviolent force for good? Meet the minds behind Eternia: a creative boss who was a feminist ally; unsung animators who became masters of analog artistry; and the shyest legend in show business. Sarah and Dave confer after watching “The Power of Grayskull: The Definitive History of He-Man and the Masters of the Universe.”