Hybrid Races

The term "race" is perhaps misused, although no suitable alternative has presented itself. The Thought-Blessed races of Wresnet often differ to the point of being separate species, but previous magical interference has made some capable of creating viable offspring together in certain circumstances.
This ability came forth in the Age of Tyranny, when it was discovered that Humans and Elves, possibly due to an unknown shared ancestor, were capable of viable reproduction. When Orcs arose later, this same natural ability was discovered in them.
While natural hybridization was considered taboo, as it was seen as a way for Humans to increase their influence and power, the tyrant-mages studied the ability to create these viable offspring and magically replicated it in the other races, leading to the creation of several new races. Dwarves and Halflings were used to create Gnomes, and Elves and Fiends were used to create Tieflings. In most cases, however, these offspring were so wholly changed that they were only capable of reproduction with other members of their new race, unless magic was used to affect the process.
With the fall of the tyrant-mages, new hybrid races are extremely rare. Humans, Elves, and Orcs can still create viable offspring with each other, which has led to the classifications of Half-Elves, Half-Orcs, and, rarest of all, Sylruks.