Wyvern

Some scholars consider the Wyvern as a distant cousin of the dragons. This is far from truth though. The Wyvern we know nowadays are the result of constant breeding of some significantly smaller, only mildly poisonous flying lizards. Over several generations, orc shamans had selected the biggest and meanest of those little beasts for breeding. Subjecting those lizards to poison and alchemistic brewages as well as constant fighting, the orcs captured and killed thousands of them. Long before the breeding cycles came to an end, the original lizard race became extinct. Originally intended to be used as weapons in wars, Wyverns proved to be too uncontrollable and impulsive to be of any real use. Finally they were used for sports events in which the orcs forced them to battle each other and other creatures. So the breeding continued for a while until the orcish society was shattered by wars and many Wyverns escaped into freedom. These new and powerful predators had no problems to survive in freedom and only their natural aggressiveness, even among each other, prevented that they became a widespread plague.