The secret of Castle Grayskull was supposed to have been that it contained a collective entity that was the combined consciousness of Eternia's ancient scholars contained in a sphere. This had to be dropped, although references to the secret remain in various episodes of the series. However, the idea was used in the new series from 2002.
Orko's name was originally Gorpo in early concepts for the shows. The character's name was changed to save on animation costs: Animators were able to flip animation cells, thus using them twice, because of the symmetrical "O".
Executive producer Lou Scheimer was instrumental in developing the concept of He-Man Mattel Toys and D.C Comics. The character had originally appeared in D.C. comics as a Conan the Barbarian-type character living in a post-apocalyptic world. Scheimer called the story "the most vile thing I'd ever read". Taking inspiration from the character Captain Marvel from an earlier Filmation series, Scheimer developed the concept of Prince Adam as He-Man's alter ego, the character of the Sorceress as his benevolent mentor, and Orko as the jester-style comic relief, to make the show more kid-friendly. Despite these changes, the show still came under fire from some groups as too violent, with some even accusing it of having hidden Satanic messages.
Legend has it that Mattell had originally planned to make a line of toys based on the 1982 movie Conan the Barbarian (1982), but balked when the finished movie was rated R. (This was before the advent of MacFarlane toys and other action figures aimed at adults.) Instead of scrapping the line, they created He-Man. Most sources agree that, while He-Man was influenced by Conan, there was no direct connection.
The character of Ram-Man was not the only person who came close to realizing that Prince Adam and He-Man were the same person., other characters were Queen Marlena in "the search", Princess Janice in " A Trip to Morainia" , and many more examples.
Even though this series ended in 1985, several "Masters of the Universe" characters (including He-Man, Orko, Skeletor, and Battle Cat) would make occasional guest appearances on the spin-off show "She-Ra: Princess Of Power", which ran from 1985 to 1987. The character of She-Ra was He-Man's sister.
While the show was conceived to help advertise the action figure line, several characters were created for the show and then later made into toys. These include Prince Adam, Orko, King Randor and The Sorceress.
Skeletor also had a lesser-known henchman by the name of Jitsu. He only appeared one time during the series. The character design made him look like he was Asian. He had a large golden hand that was used to give karate chops to his enemies.
Several action figures which were made in 1986 were added to the cast of She-Ra: Princess of Power (1985) because production on Masters of the Universe had ceased: Rokkon, Stonedar, Snout Spout, Multi-Bot, The Horde Trooper, Rattlor, Tung Lashor, and a character named "Colonel Blast" who appears to have been based on the figure Rio Blast.
The Evil Horde, the antagonists from She-Ra: Princess of Power (1985), make an appearance in one episode, "The Origin of the Sorceress". In that episode during a flashback, we see several reptilian soldiers wearing Horde logos functioning as scouting party before they're chased off.
Linda Gary, played Teela, The Sorceress, Evil Lyn and Prince Adam's mother, Queen Marlena, but on several occasions, Marlena's voice was substituted by executive producer, Lou Schiemer's wife, Jay. This was because the 'official' voice actors such as Gary had it stipulated in their contract that they could only perform three voices in each episode. Therefore, Jay and her daughter Erika would often perform uncredited voices when needed.
Filmation's long time composer Ray Ellis declined to work on this show because as a composer, he was never paid anything up front, only from residuals when the music was aired on TV. Since this series was the first to try out the straight to syndication market, Ellis was afraid he would never see any money coming in. Shuki Levy and Haim Saban had no problem accepting the deal, and started working on two straight to syndication shows simultaneously: He-Man and Inspector Gadget.
The reason certain characters differed from their toy counterparts is that Mattel were often developing action figures at the same time that Filmation were producing the cartoon series. During production of the cartoon Mattel would hand action figure concept illustrations to Filmation, which the studio would use to create the animated versions of the characters. However, by the time the action figures were released some radical design changes may have taken place, resulting in them looking nothing like their animated counterparts.