Mangog first his first appearance in Marvel Universe in July 1968 in The Mighty Thor # 154. After Thor knocked Ulik into Abyss of Shadows, but in order to save his life he grabs on a small clif where he finds a mystical cliff, seeding with Odin power that says "Let no living being destruct what lies within by the order of Imperial Odin". Thinking that anyone who is an enemy to Asgard would be an ally to him, he moves the Enchantisone blocking the path, thereby freeing Mangog for the first time. Mangog explains that he is the very embodiment of an entire race, that once fought Asgard and it was Odin who killed them and Mangog was created out of their combined hatred, fueling him with the strength of billion billion beings. This is later revealed to be slightly untrue in The Mighty Thor # 157 where Odin reveals that Odin did not kill the said said but rather used Odinspell to trap the beings into a mystical prison and it was the prison itself that took the form of Mangog.