We call them Yin Yang Dragons, but really they are two separate dragons: the Yin and the Yang. The Yin is a grim, calm dragon, while the Yang is a whirlwind of emotions. Having two contrasting personalities attached to the same body can be difficult- fights are common - but the presence of both personalities makes them wiser as a whole.
The Yin and Yang Dragons rarely agree about any subject, least of all what direction to fly. The Yang is constantly on the hunt for adventure; if there's a bushel of Firapples to eat or a battle in the Arena, the Yang is eager to stick its neck out. The Yin, however, prefers to stay the course and preclude itself from such affairs. The result is a dragon that wobbles from location to location, unable to fly in one direction for long.
Adult Yin and Yang Dragons have spent a lifetime snapping at each other's heads, each with its fair share of bite marks and bruises. But while each dragon is headstrong, both the Yin and Yang realize that the other's opinions matter, and they are more willing in their old age to compromise.
Epic Yin Yang Dragons have gone through their entire lifetime of having two heads on one body. In this ultimate form, the two dragon heads are at peace with one another. Having listened to the wisdom of their other head for so long, the Yin and Yang are more balanced dragons, each having the positive mental attributes of their counterpart. Each is as open-minded and knowledgeable as any dragon could hope to be.