'What will you do now?' Nick thought. 'Humanity is regaining control of the world, and if you don't act now, I will expose one Fallen after the other. All the Fallen working for your Corruptors will be captured.'
This was the plan.
By talking to Hatred, he exposed that he knew where it was.
This alarmed the Adversaries, and they all gathered together so that none of their elite could be picked off.
But that released their hold on the world, and as long as they stayed in one place, humanity had the freedom to deal with all of the cities.
Without the constant fear of an ambush by a Corruptor, the Protectors could travel from city to city and eradicate the hold the Specters had over them.
If the Specters didn't do anything, they would lose control over almost all of their cities.
While none of the elite would die, they would essentially lose all of their food supply.
Naturally, Death could see what was going on, and it knew that it had to do something.