@MAST: Nathan Drake feels no remorse sure Marston and Niko are killers but they see themselves as criminals looking for redemption. Nathan Drake may kill may also just bad people but he should show a little resentment for what he's doing. The reason people see him as a psychopath is because of his lack of remorse. People in war are trained to kill and still struggle with the idea of killing people. Drake doesn't.
Don't take this the wrong way I like Uncharted but I see where the whole Drake is a psychopath comes from.