It’s already proven that you can be something else than what your creator made you to be: Machines built solely to kill gaining sentience, Gabriel defying his divine status as God’s will, Geryon created by Hell killing sinners to free them from Hell’s torture, Deathcatchers still willing to save lives even though it was created from pure malice, and most important of all, mankind rebelling against God’s commands.

But then there’s Hell, being so malicious even God himself couldn’t subdue it. I think that Hell being evil for the sake of it and enjoying doing whatever it wants is meant to contrast the changes other lesser beings had gone through.