I think it's ultimately us people who decide among ourselves what's good and what's bad. The universe functions the way it does without regard for justice or morality, but people have hearts, and they get hurt, and they feel that what hurts them is bad.

Nyx was awakened, and Nyx arrived to bring an end to the world, because of Erebus. Erebus was born from all of our hearts -- because... because so many people lost sight of what it meant to be alive, and we unconsciously sought death. We fought and tried to stop them, but neither of them did anything just to hurt us.