Invitation From The Eldest's

Lisa could only go with the flow. 

It wasn't as if she and Cain didn't care about unjust or the cruelness of society. But rather, they know they have their own lives to live as they can be easily ruined just like any other poor person.

Cain knows for sure a number of people would have the same indifferent reaction when confronted with poor or homeless people. 

And it was indeed selfish to those people.

Cain never justifies his actions for some greater cause. Rather, he believed he was being realistic and rational so that he and Lisa could live comfortably. 

Moreover, at this time, Cain was still in the midst of giving meaning to his life.  His sympathy was almost non-existent at this point. 

And it was this mindset that stuck with him like a spider web. 

....

When blinking his eyes as the memories faded away, Cain's lips slightly curled.

It was a smirk of slight amusement.