He-Ro makes an unnamed appearance depicted in shadow in the last page of the mini comic Power Of Grayskull: The Legend begins. We see him using the power of his staff to send the forces of King Hiss back to his domain, as well the time traveling He-Man, Sorceress and Skeletor to back to modern Eternia. This action prompted He-Man to ask the question many fans have wondered for years...Unfortunately the second and third parts of the PoG trilogy never where produced leaving many unanswered questions in 1987.
Eventually He-Ro's offical bio surfaced
Identity: Secret (ancestor of He-Man and She-Ra)
Real Name: Hero, alter ego of Gray
Role: First recipient of the Powers of Grayskull and original leader of the heroic forces in prehistoric Eternia against the evil DinoReptilian Kingdom
Power: As well as possessing the fabulous strength of He-Man, He-Ro has another power uniquely his own. It is the power of natural magic: an ability to magically influence elements of nature. He-Ro draws his power from the Book of Transformation.
Character Profile: Reared under the tutelage of his mentor, ELDOR, and the tribal chieftess, Sharella, Gray was one day mysteriously drawn to a nearby cave. There, in darkness and in light, he was invested with the newly evolved powers that would change his his life and alter the course of history in Eternia. The exact details of what transpired in that cave have remained secret, but Eldor has made cryptic allusions…references to the boy's mysterious past, to an amazing legacy… and an awesome task which Gray accomplished that day in the cave. By placing one hand on his heart, flexing the other arm into a muscle and incanting, "Magic and strength…tempered by heart!" Gray causes an amazing transformation to occur, becoming the He-Ro of Grayskull and announcing, "I stand for Peace!"
Weapons: He-Ro channels his energy through a marvelous staff which can direct a magic ray to specific parts of the environment, causing the likes of inanimate rocks, rivers, and trees to respond to his commands.
Note: With powers of this scope, it might seem ludicrous to suggest anyway in which He-Ro could be less powerful than He-Man. But He-Man does have one power He-Ro lacks: the power of wisdom and maturity. He-Ro is younger and still learning to use his powers.