Copperhead has kind of an intresting story.  You see, He-Man.org forum member, Glaxay Warrior, notice in a German Masters of the Universe mini-comic that there was a character charging forward with Skeletor's minions that looked like Cobra Khan.  No biggie, because until the Snakemen were introduced, Khan was on Skeletor's side.  However, this character seemed to have a hook for a right hand, similar to Trap Jaw, which Khan did not have.  Thus, Copperhead was born.