Fall of the Warlock Kings
In the mythical history of Chan, it is said that during the first years of the city certain rebellious hobgoblins made deals with dark powers to seize control of the land. These being became tieflings, corrupted by the power they accepted, and were driven forth into the wilds. In time, they became numerous, and grew to rival the hobgoblin race that they had sprung from. Now, centuries later, the situation is still much the same, with the two races being rivals for control of the Plains of Chan, though the hobgoblins, with their servant races, are able to get the best of the tieflings for the most part. The rivalry is almost friendly by this time, though in times of trouble pogroms of one race against the other do arise on occasion.