This t-shirt features the logo for what is widely considered the greatest animated series of all time, Masters of the Universe. In Masters of the Universe. In Masters of the Universe, Prince Adam defended the secrets of Castle Grayskull by transforming into He-Man when he raised his sword and said, "By the power of Grayskull! I have the power!" He-Man and his friends Orko, Man-At-Arms and Teela battled Skeletor and his Evil Warriors in each exciting episode.