As indicated by the title, the series was to focus on a new character, He-Ro, the adopted son of He-Man. Although He-Ro shares his name with the ancestor of He-Man that was to be featured in Mattel's aborted The Powers of Grayskull toy line, the show bible makes no reference to this and draws no connections to the earlier character.
The New Adventures of He-Man has no connection to "He-Ro Son of He-Man". There is a rumor that NA He-Man started out with this storyline and Dare. This is not true. Currently there is no documentation to support it. All the concept-art and ideas from people working on the New Adventures (Roger Sweet, Mark Taylor and Errol McCarthy) never had any mention of Dare or such storyline.
The He-Ro series follows the continuity of the classic 1980s cartoon. (The show bible makes no reference to The New Adventures of He-Man however there is a strong connection to She-Ra: Princess of Power as the bible vaguely hints that Dare will eventually be revealed to be the biological son of Adora and Sea Hawk; a fact later confirmed by Lou Scheimer himself.) Ten years have passed since Skeletor was banished to the Frozen Lands of Eternia and Prince Adam became king following King Randor and Queen Marlena's retirement. The Sorceress informs Adam that prophecy requires him to go to the Mountains of Fire to seek out a boy who will inherit Adam's Power Sword.
Coincidentally, Skeletor has just managed to escape his prison and learns of this prophecy. He and his associates find the boy—a savage raised by a wild bearcat—and convinces him that He-Man is responsible for the death of his "mother." Although Skeletor begins to teach the boy the ways of evil, He-Man arrives in time to make him see reason. He-Man names the boy "Dare" and brings him back to the Royal Palace, where King Adam and Queen Teela adopt him as their son.
Adam is reluctant to pass on the Power Sword, but a final confrontation with Skeletor forces him to choose between losing his kingdom or sharing the sword with Dare. With help from Zoar, Dare uses the Power Sword to transform into He-Ro, and turn his companion Craven into Battle-Bird, beginning his quest to defend Castle Grayskull from the evil forces of Skeletor.
- He-Ro/Prince Dare - Dare has special abilities due to being raised in the wild, such as super-senses and the ability to communicate with animals. Whereas Adam and He-Man are presented as being the same age, Dare is an awkward thirteen-year-old while He-Ro is a mature young man.
- Kay-La - The love interest for Dare, who is assigned to educate and civilize him following his adoption. Her role is essentially that of Teela's in the He-Man series. Kay-La is described as the niece of Man-At-Arms. Whether she is specifically a blood relative to either Duncan or Teela is unclear.
- Craven/Battle-Bird - Craven is a large crow that Dare has taught to speak like humans. Whereas Cringer is too cowardly to fight, Craven is eager but incompetent. When He-Ro transforms him into Battle-Bird, he becomes large enough for He-Ro to ride upon. In both of his forms, Craven has a contentious relationship with Cringer/Battle Cat.
- Air-Bag - A blustery hothead with the power to inflate like a balloon and expel super-breath.
- Fork-Lift - Has fork-like arms capable of lifting anything and flipping it over his head behind him. Described as "a cross between an Olympic weight-lifter and Godzilla."
- King Adam/He-Man - Although Adam's secret is still not publicly known, he doesn't spend so much time acting irresponsible to conceal it, and is now seen as a capable ruler. The show bible allows for the possibility of Adam having occasional solo adventures as He-Man as well as He-Man/He-Ro team-ups.
- Queen Teela - Referred to as "Tee-La" throughout the show bible. Teela easily fell for Adam when he began behaving more seriously. She evidently still does not know that he is secretly He-Man, or that Dare is He-Ro.
- Man-At-Arms - Still playing the same role as he did on the original series.
- The Sorceress - Her role is exactly the same as on the He-Man series.
- Orko - He is described as having not changed since the original series, although the show bible erroneously states that he was as incompetent a magician on Trolla as he is on Eternia. Orko is described as having an uncle "Dorko" (presumably meant to be Montork) and a girlfriend named Dree Elle who are both better at magic than he is.
- Cringer/Battle Cat - As Cringer, he has been tasked by Adam to keep an eye on Dare. When Dare becomes He-Ro, he can use the Power Sword to turn Cringer into Battle Cat to serve as his steed. An image in the bible depicts He-Ro riding a blue lion which is presumably a redesign of Battle Cat.
- Man-E-Faces - Completely redesigned in the show bible, although his character is unchanged.
- Ram-Man - Still the same lovable lunkhead, but now in a new black costume.
- Bug-Eye - Commands insects just as Beast Man controls large animals.
- Slob-Boar - Described as "Half man, half pig, all slob."
- Tongue-Lasher - Presented as a brand new villain despite the obvious similarity to Tung Lashor. His whip-like tongue can cut through solid rock.
- Missile-Toe - A villain with heat-seeking missile launchers on his feet.
- Saw-Tooth - Has serated blades for teeth.
- Ever-Mean - A paranoid half-man/half-plant.
- Odar - A human skunk whose stench is a powerful weapon. Odar is listed as a new character, suggesting that Lou Scheimer had forgotten that a similar character, Stinkor, already existed.
- Skeletor - the primary adversary of He-Ro. Skeletor is described as ageless; the only new developments for his character are his bitterness about his ten-year imprisonment and a new magic staff.
- Panthor - Skeletor's pet and sworn enemy of Battle Cat.
- Evil-Lyn - While largely the same as she was in the original cartoon, Evi-Lyn's costume is redesigned to be more revealing, and she has a more distracting effect on the new, younger hero.
- Beast Man - His role in commanding animals to search for Dare and slay Dare's adoptive mother is critical to He-Ro's origin. Otherwise he is still the same lumbering brute too stupid to stand up to Skeletor.
- Mer-Man - Whines and complains when he must operate on land instead of the sea.
- Trap-Jaw - Described as "the really stupid one."
- He-Ro Series Bible on He-Man.org