<p>If Unulaq had stayed fuzed with Vaatu, and Korra had killed him out of his avatar state, would the next "dark" avatar be evil? Would they have an inclination for being evil? Could they fight that and be heroes? Would they only be born in the water tribe? They could only be a waterbender, but that doens't necessarily mean that they would be born there. </p><p>And, in 10000 years, if all of the different nations interbed, and there weren't any uh... "pure" water/fire/earth/air bender descendants, would the avatar be reborn in anyone, or no one? </p>