"I believe...
...that people can go through ten times what he went through and still never hurt a fly."
This made me wonder about his back story, because the way he would know that, is because he or someone close to him must have been through something really awful, and come out of it still a decent person.
I personally know there are plenty of people that go through truly awful situations and are still so sweet, kind and gentle. It sometimes annoys me that films and TV rarely show that. They always use it as some backstory justification for why the antagonist is so cruel.