The common origin story for half-orcs is that they are a supernatural response to the existence of orcs. …Half-orcs are most common outside the Empire in the barbaric wildlands. Until the last century or so, half-orcs were rare inside the Empire except on the frontier. – 13th Age
Half-orcs are common in the Black March, and the people who govern or have settled in the province have mixed reactions to them. Many see them as potentially valuable in dealing with the orc tribes as sources of insight and information, or as fighters who can match an orc warrior’s fearsomeness. If they look sufficiently orcish, they may be sought out as ambassadors or even infiltrators.
(Of course, just because someone is a half-orc doesn’t mean they’re experts on orcish culture or can speak the language. Other races — with the notable exception of half-elves — just can’t seem to grasp that.)
Others, who take the rise of the Orc Lord seriously, are wary of half-orcs. If he succeeds in uniting the orc tribes into a vast, disciplined army, can the half-orcs be relied on to stand with the Empire? Or will they join the horde?
Half-orcs have no doubt that the Orc Lord exists and has the potential to unite the tribes. In fact, nearly all of them have been approached at one time or another by orcs who tell them that a new day is coming. These orcs say that there is no such thing as a “half orc” — they are true orcs, and their place is with the tribes. They encourage the half-orcs to join their brethren beneath the mountains and help create a brighter tomorrow under the banner of the Orc Lord.
The half-orcs can’t help but note that no human, however friendly, has ever said anything like that to them.