Of course, Azief doing this is not because he felt responsible but because of Katarina.
But, after knowing the people of this world, if he still remains heartless, then he is not quite human.
Before, he could care less about what happen to this world.
But once you know the people in it, even though you would not sacrifice everything for them, you would still have some empathy and since it is not something that is hard for him to do, why not help them?
Both and he and Katarina is doing the best they can.
A perfect world where everyone understands each other, at least in this world, could not be realized.
Azief and Katarina himself did not know what a perfect world would look like. One could say Earth has developed to a high level.
And after the Fall, the advancement become even faster.
But even then, this did not mean the problem are all solved.
