Warcraft Total War is a total conversion mod for Medieval II Total War. Our goal is to bring the Warcraft universe into a Total War game. This mod will feature epic battles with units from the Warcraft universe and a new campaign that will cover the events of the Third War and beyond.
The Orcs are currently the very same for the Dark Horde, the Horde and the Fell Orcs of the Burning legion - but there may be changes made before a release.
The Dark Horde has most variation in units. The difference currently otherwise is just textures.