Masters of the Universe (1987)

The world of Eternia in the aftermath of Skeletor's war on Castle Grayskull, which he has won after seizing Grayskull and the surrounding city using a cosmic key developed by the locksmith Gwildor. The Sorceress is now Skeletor's prisoner and he begins to drain her life-force as he waits for the moon of Eternia to align with the Great Eye of the Universe that will bestow god-like power upon him.