(notes from a lecture presented on the slopes of Mount Audarammas, approximately 800 years after the founding of Aure, preserved in the Great Library)
...can any deny that our greatest foes are the remnants of previous empires? Nay, even now, the discarded remnants of decadent Zahar threaten us all! While they overthrew the cold-blooded Thrassians, they continued their former masters' tradition of magical cross-breeding, creating foul monstrosities to blight the land. Ancient sages say the Thrassians themselves were created out of giant lizards and primitive man, though none claim to know who performed this deed; better for us all if they hadn't. The Troglodyte was likely a creation of the Thrassians or their former masters, creating scouts and spies by mixing chameleon into the bloodline of the Thrassians. These were the only ones to appear before dread Zahar.
Once the Zaharans learned the techniques, they applied them gladly. The most flexible of the lineages they created was the one descended from gnomes and trolls. While the Gnolls themselves were somewhat flawed, disliking the daylight and not very intelligent, the Gnoll formed the basis of the Goblin, along with an admixture of dwarf traits. While a failure on its own, the combination of dwarven resiliency and trollish fortitude meant this line had some promise if its less desirable traits could be removed. This led to the crossing of the goblin with man, and the creation of the Hobgoblin. These were strong, intelligent, and militaristic, but relied on heavy logistical support for their armor and weapons. The penultimate attempt to improve this line crossed the Hobgoblin with the bear, creating the Bugbear. While naturally tough, the Bugbear proved to be almost suicidally courageous and nearly as dim as Gnolls, which made them useful shock troops, but difficult to keep around in significant quantities. Finally, someone attempted to cross the Hobgoblin back into its troll ancestor, twisting the mixture by adding the essence of a ghoul as well. This created the Throghrin, which served well as the leaders of the Hobgoblins. However, the addition of the ghoul essence meant the creation of new life is difficult for them; they breed uncertainly, and many of them were recorded as being completely sterile.
The Zaharans also had three other lineages that were less successful in terms of being able to be molded into new shapes, but they are still quite dangerous. The Kobold may have been an attempt to demoralize the remnants of the Thrassian Empire, crossing those proud warriors with dogs. The resulting creatures were selectively bred for weakness and cowardice, although the abuse they suffered as proxies for their ancestors also left a streak of sadism that still remains. While generally following the Zaharan pantheon, recent excursions into Kobold warrens suggest the rise of a new religion among them, worshipping a previously unknown god, Tkkr. The second lineage was the Orc, created from man and boar and getting the worst traits of both - gluttony, greed, stubbornness, sloth. They also breed rapidly. In their society, if one can call it that, each polity is ruled by the strongest male, with subordinates each ruling their own smaller factions. Take out one near the top, and all of his former subordinates will being in-fighting to take over the spot. Only a strong ruler, generally a non-orc who has cowed them into submission, can prevent this from happening if one of his subordinates dies. The last of the foul creations was the Ogre, created from man and ape. They were intended solely as shock troops, and as we know all to well, there are few to meet their awful talents at this. Their intellect is closer to the ape than the man, and while occasionally able to develop an ambush or a trap, they are easily the least intelligent of the created races. This is fortunate for the rest of us. Orc chieftains will often try to have ogre bodyguards, as this limits the number of assassination attempts on the chieftain.
Given that our greatest foes were created by the previous Empire, one does wonder whether a better solution might not be to sail to lands where these abominations were never created...
(Notes: the gnoll -> goblin -> hobgoblin -> bugbear and throghrin is the way the lineage has to run, based on each monster's description in the core book. The suggestion that the troll's Regeneration or the dwarf's Hardy People affected the lineage is entirely my own creation, but it does make one wonder what could be done by crossing a Thrassian or an Ogre with a troll or dwarf...)