Roger Sweet , a toy designer who created the musclebound hero He-Man for Mattel as well as other characters for the popular Masters of the Universe cartoon and toy franchise in the 1980s, died Tuesday. He was 91. Mattel confirmed the death in a statement, which did not cite a cause or say where he died. Sweet was a resident of Lake Stevens, according to The Daily Herald of Everett . “Roger played a pivotal role in the early development of Masters of the Universe, helping introduce iconic characters including He-Man and Skeletor to the world and inspiring generations of fans to find their inner power,” the statement said. “His legacy endures in the characters he helped bring to life and the imaginations he ignited.” The He-Man character arose from a missed opportunity.…