William "Billy" Cranston (Guardian Force)

William "Billy" Cranston is a middle-aged scientist from Angel Grove. In high school he served as the Blue Ranger of the Mighty Morphin Power Rangers, but he later retired and eventually moved to the alien planet of Aquitar in order to be with an Aquiatian woman named Cestria, whom he fell in love with. He spent the next decade or so there, but returned to Earth at a later date for unknown reasons. After discovering a strange alien capsule, he learned of an ancient war between two alien races known as the Malayim and the Seihades. After learning that the latter had obliterated the former and were on their way to Earth, he moved back to his hometown of Angel Grove in order to recruit a new team of Rangers and repel this incoming threat. He now works at his old high school as a Chemistry teacher while moonlighting as the mentor to the Guardian Rangers. He is portrayed by David Yost.