Black Orcs are physically biggest and strongest of the related green skins species their skin is much darker green in skin tones than that of Orcs, Goblins and Hobgoblins. Black Orcs are more intelligent as well are often seen to be leading the Orc tribes, they tend to be better armed than other Orcs so they wear heavier armour and carry around larger weapons.
Black Orcs tend to be much better organised and infighting within a tribe does not succumb to petty squabbles. Other Orcs tend not to squabble when black Orcs are around either because they don't want to be picked on by their bigger cousins.