Hawkfang had created this technique in order to take revenge upon the Sithe. He wanted to take revenge for both his father's sake and his own sake, and for the sake of the countless deceived Sithe descendants! They were viewed as disposable cannon fodder by the true Sithe, while even his father had been forced to take part in the war.
"The two of us, father and son… we certainly share a sorry fate." These words continued to stab against Hawkfang's heart like knives. He would never be able to forget that look on his father's face. This was why he needed revenge.
He wanted to create this technique, then find a way to deliver it to the cultivators! He felt certain that the cultivators would be able to use it to dramatically increase in power, producing many new Hegemons and even new Autarchs. That way, the Sithe would be defeated.
