Hedona - Fall of the Magister Lords
Half-Orcs are typically the result of Orc Pillaging and rape. Though rare cases of genuine partnerships between Orc and Human have been heard of, the most common cause of Half-Orc births are Orcish raids.
The Orcish tribes often raid small settlements and typically rape unprotected women.
Half-Orc children are often not wanted by either race and end up living the lives of beggars or criminals. There are rumors of some half-orc tribes existing, though these are unconfirmed.