Origin #1 (Mini-Comics/MOTU Adventure Magazine):
The evil demon warrior, Ninjor, along with Scare Glow, were summoned from the Dimension Of Noir, by Skeletor, to do his bidding. In "The Search For Keldor", the two Evil Warriors are summoned to prevent the Heroic Warriors from the truth about Keldor's fate. Skeletor believes that the truth could destroy him. In the story "Enter...The Ninjor" they arrive in the same fashion as the mini-comic, but are sent to destroy He-Man.
Origin #2 (MOTUC Bios):
Armed with nunchucks, a longsword and longbow, this awful assassin was summoned from another world by a spell of light to serve Skeletor on Eternia. His mission is to eliminate all of the Heroic Warriors one by one until He-Man no longer has any help in defending Eternia. This Ninja Warrior, sometimes called "Ninjor" by his foes, always moves with great speed, skills and silence. His true motivation however has been kept secret from all. Even while serving Skeletor, he reports back to his true master, Horde Prime, detailing Skeletor's weak points and how to exploit them. Ninjor appears out of nowhere to ambush Heroic Warriors!
MOTU Mini-Comic Appearances:
MOTUC Mini-Comic Appearances:
Marvel/Star Comic Appearances:
MOTU UK Magazine Appearances:
MOTU UK Adventure Magazine Appearances: