They will never feel bad or regret it at all. Their moral system is completely different from ours.

They see things in a matter of Strong vs. Weak. To be Strong is good, to be Weak is evil.

The things they do show how Strong they are. And the things we suffer, and our incapability of doing anything about their deeds, show how Weak we are.

They have nothing but contempt and hate for us. They see themselves as superior, post-human, almost divine. God doesn’t fret the lives he takes, the sacrifices he demands, the suffering he causes.