Yup. And there are a million ways to fit him into continuity. The easiest is having him be one of the precursors to He-Man. Heck, he could be the same He-Man as Adam. What if he was a more savage barbarian, but his merging with Adam is what gave He-Man his humanity - making him the one true "He-Man"?
Wow. That's like Marvel's Thor or Captain Mar-Vel, where Thor and Donald Blake are two different beings. It's an interesting take on Adam transforming into He-Man, because usually He-Man is just a powered up Adam, not his own personality.