He-Man and the Masters of the Universe - Season 1 - Eps 30: The Return of Orko's Uncle
A villain called Azrog is arrested on Trolla by Uncle Montork, but he flees to Eternia where he joins forces with the witch Spydra. Montork follows him, but ends up imprisoned in Spydra's castle. When He-Man, Battle Cat, Teela and Orko go to rescue Montork, Orko falls under Azrog's spell and becomes evil, and is set against his friends.
About He-Man and the Masters of the Universe

Title: He-Man and the Masters of the Universe
First Air Date: 1983-09-05
Last Air Date: 1984-12-08
Status: Ended
Rating: 7.3/10 (from 369 votes)
Language: EN
Seasons: 3
Total Episodes: 130
Network: Syndication
Genres: Action & Adventure, Animation, Sci-Fi & Fantasy, Kids
Production Companies: Mattel, Filmation Associates
Synopsis
When Adam, Prince of the planet Eternia, raises his magic sword he transforms into He-Man (the most powerful man in the universe). With his allies and friends, he battles the evil Skeletor and his minions to protect the secrets of Castle Greyskull.
Cast

John Erwin
He-Man / Prince Adam / Ram Man / Beast Man / Whiplash / Webstor / Faker / Granamyr (voice)

Alan Oppenheimer
Skeletor / Battle Cat / Cringer / Man-at-Arms / Mer-Man / Buzz-Off (voice)

Linda Gary
Teela / Evil-Lyn / Queen Marlena / Sorceress of Castle Greyskull (voice)

Lou Scheimer
Orko / King Randor / Stratos / Mekaneck / Man-E-Faces (voice)

Erika Scheimer
Arcadian women (voice)