Comment by Mega on Kai

It's from warhammer 40k. It's the words of Horus Lupercal from the Horus Heresy.

"I never wanted this. I never wanted to unleash my legions. Together, we banished the ignorance of Old Night. But you betrayed me, you betrayed us all. You stole power from the Gods and lied to your sons. Mankind has only one chance to prosper, if you will not seize it, then I WILL. So let it be war, from the skies of Terra to the Galactic Rim. Let the seas boil, let the stars fall. Though it takes the last drop of my blood, I will see the galaxy freed once more. And if I cannot save it from your failure, Father, then let the galaxy BURN!"

Edit:

You can watch the trailer where the line came from on youtube.