One of the themes I work with in my Orion the Hunter stories is that integrity is a spectrum. The left end is pure altruism, the right pure narcissism. Most of us float near the middle of the spectrum on most days, some a bit to the left or right. Neither saint nor completely self-centered. We consider ourselves good people and go about living our lives.
For many of us, though, we are just one bad day away from making a significant slide one way or the other on that spectrum. Did you lose your job today? What is your response? Do you start volunteering to fill your downtime, or do you start robbing banks to make up the lost income? How much is that decision impacted by a wife and kids? By a high-end lifestyle?
Do you think you’d never kill another human being? What if your child was endangered? What if your wife had been killed by that person? What then? How far do you slide?
What about a policeman that takes bribes, but in doing so keeps the peace in his neighborhood? Maybe he takes money from one gang to make arrests n another gang that’s threatening their territory. Where on the spectrum does that fall?
Our actions and reactions are often related to our situation. We are complicated machines, we human beings. I try to reflect that in my characters. Especially in my protagonist Orion. He could easily be seen as a bloodthirsty psychopath, but I work to make him seem more honorable, more human than that.