Orcs/Half-Orcs

Orcs were created by the god Gruumsh towards the end of the age of primordials at the same time Corellon and Moradin created Elves and Dwarfs. As the story goes when they 3 were claiming lands to place their creations, everywhere Gruumsh would choose would be already claimed by one of the other two. Everytime Gruumsh would find the land was already claimed, Correlon and Moradin would laugh in his face. And so Gruumsh made his Orcs desire to strip away the lands of Elves and Dwarfs to reclaim their rightful homes. For this reason, Orcs have been forever at war with Elves and Dwarfs and any other race for that crosses their path.
The Orcs second most reveared diety is the goddess Luthic. If Gruumsh gave the Orcs their strength, brutality and bloodlust, then Luthic gave the Orcs cohesion, unity and strong reproduction capabilities. Luthic allowed the orcs to be more than mere unorganized raiders. Orcs also breed without descrimination, whether that be orcs or anyone unfortunate enough to be on their warpath. The child of an Orc and different race will always become a Half-orc. Accept in the case of Ogres, no visible race specific traits of the non-Orc side will ever be carried over. Personality traits though may transfer as normal. In society, Half-Orcs are often mat with disdain and mistrust, and in the case of Dwarfs and Elves, Hatred. Though nobody hates Half-Orcs more often than they hate themselves and their people. Half-Orcs born to non-Orc mothers often find a deep hatred for Orcs. Afterall, few of these mothers have good things to say about their "fathers" and the way they were concieved. Needless to say, Orc fathers don't stick around and these women are left to care for children that bare to them no resemblance.
When the humans landed on Therin, and war broke out between Elves and Humans, the Humans would use the Orcs' armies to gain an edge on the Elves. Humans would wait until just after battles between the Elves and Orcs to attack. They would hit the Elves again when they were still recovering.
Once the Elves were kicked out of Alvenloch, The orcs would slowly disperse as well, seeing as how their enemies had moved on. New Orcish populations grew in the mountainous outskirts of the Elves new homes.
In the case of Dwarfs and Orcs, little change in location has occured since the Dwarfs settled in Dhonfarum. Heavy populations exist in the East and Southeast ranges of Dhonfarum, and are a constant annoyance to the Dwarfs. The Dwarfs have had an easier time repelling the Orcs armies than the Elves did. Many other dangers such as Dragons and Giants are a contant source of danger to the Orcs and so occupy most of their attention.

Orc

Half-Orc