Dude, original ogres have always had a single head since "Warcraft 1: Orcs & Humans" (
Ogre (Warcraft I) ), two-headed ogres are a mutation that appeared for the first time in "Warcraft 2: Tides of Darkness" (
Ogre (Warcraft II) ) without us really knowing their origins, it's also from this second opus that these same ogres were enhanced by Gul'dan by infusing them with the magic energy drawn from the Runestone of Caer Darrow Island.