From the latest Fan Pack:

Orcs have been a part of Might & Magic for a long time, and their design changed numerous times throughout the long history of the series. From the pig-like humanoids of Might & Magic II to the fierce tribal warriors of Heroes VI, you'll notice the Orcs kept one consistent characteristic in nearly all Might & Magic games: their orange-brown skin (the notable exception being the green-skinned Orc of Heroes III).