Countless worlds knew me as their guardian…
...I was trusted to uphold the Oath, to defend the creations that my brothers and sisters worked tirelessly to perfect.
The Nathrezim came from the darkest regions of the universe. They were the greatest threat to the mortals that I have ever witnessed. Without mercy, the demons invaded other planets, slaughtering and burning anything that resisted. To a lesser being, an intimidating foe. I was charged with the extermination of their race upon their homelands, foreign to most of my kind. By my hand, they were vanquished and imprisoned. But within their planet I sensed a great, living darkness. A parasite of worlds. A real danger to my own people. I have been enlightened as to why the demons have suddenly encroached upon other territories. It was not for conquest, but to escape.
I tried to warn my brethren. I advised to abandon the lesser beings to protect our own kind. However, their weakness for the mortal pets kept our strength divided. They do not comprehend what threatens us beyond their high walls. They do not understand the nature of conflict as I do. The weak perish, the strong prevail. So it is, so it has always been.
What is life worth? Countless eons of battle? Our own planet? We have already sacrificed so much for their survival. For what? The mortals only dishonor us. The approaching shadows I've seen will inevitably consume all life. All my efforts to protect them will be in vain. We cannot tax ourselves with responsibility for them at the expense of vulnerability. My brothers and sisters foolishly cling to their archaic Oath. I will not risk our own people over such insignificant creatures.
I have freed my prisoners of war. Creatures of immense power from across the nether, bound to my will. The greatest army ever known. My brothers and sisters of the Pantheon, allow me to simplify your divided attention. Watch as I destroy the mortals you hold more dear than your own people. I accept that in doing so I will be your enemy, but take comfort in knowing I am also your savior."
- Sargeras, the Guardian