Necromancer: Leah is gone. The power that slept within her belonged to Diablo. And he is reborn, stronger than ever. The Heavens were his true target all this time. And now the angels stand on the brink of annihilation.
Templar: This devastation defies all reason!
Tyrael: Imperius, you cannot mean to face Diablo again! Your wounds are barely healed!
Imperius: The Heavens burn. This is your fault, Tyrael! And you, nephalem! Look below and see what your kind has wrought!
Templar: I know how he feels, but we have to keep going!
Talk to Tyrael at the Diamond Gates
Tyrael: The Diamond Gates have stood since the light first broke over the High Heavens. Now they lie in ruins. Imperius is right. I am the cause of this.
Necromancer: You could not have foreseen it.
Tyrael: Long ago, my brethren and I voted to decide the fate of man. I cast the final vote that spared you from extinction. Now... humanity has birthed the Prime Evil.
Necromancer: Demons manipulate angels and humans alike. I can assure you of that.
Tyrael: But you don't understand. Hope has been silenced.
Enter the Vestibule of Light
To make matters worse, Tyrael has lost his will to fight. He even seemed to regret defending humanity from extinction all those years ago... I cannot pretend to understand the heart of an angel, but his sudden melancholy is most strange. Perhaps there are other forces at work here...
Note: Enter the Vestibule of Light portal.
Diablo: Gaze upon the destruction I have wrought. It will be the last thing you see. Iskatu, destroy the nephalem!
Iskatu: I do not fear you, nephalem. You'll find only death in this eternal realm.
Kill Iskatu and his minions
LOCATION: THE VESTIBULE OF LIGHT
Shadow Vermin spawn from all directions and attack the nephalem.
Diablo: Every moment I delay you, I draw closer to my ultimate victory.