the tale of 2 sides

Niaris, former king of the thresians, the dark ruler, the most powerful of the evil Thresians known as the "darker ones".. he ruled mercilessly, preparing to kill the ones who stood up to him..

Arias, she was queen of the lighter side of the thresians, or the "protectors" they ruled with fairness, protecting humans from monsters and the darker ones..

then suddenly, after a battle.. a strange occurrence happens

what happens when dark and light join forces?