Sir Warwick Harrow : You have to finish it, lad. You have to finish it. For a man to lay beaten... and yet breathing? It makes him a coward.
Mal : Sure. It would be humiliating. Having to lie there while the better man refuses to spill your blood. Mercy is the mark of a great man.
[lightly stabs Atherton with the sword]
Mal : Guess I'm just a good man.
[stabs him again]
Mal : Well, I'm all right.
This show is not only one of my most favorite and dearest to my hearts but I have never believed there is Good Vs Evil. I have always believed their is Good and Evil inside of us all. For some it comes easily, naturally, and for others it takes being held at gun point to draw it out of us.
However it is truly the sign of someone strong to walk away from a fight knowing that the moment they turn their back someone might still have the audacity to have lost the fight and still attack when they think they have the upper hand. That is honestly how you reveal cowards and bullies. They never want to fight you when you stand there brave, strong and looking them dead in the eye.
For me it honestly depends on what you have done to determine if I will walk away. For me if I am your villain in the nightmare you have created for yourself then you deserved that side of me. I have no qualms with giving you mercy but you better believe me I will never back down from something strong in my path.
If you want mercy you better damn deserve it. For many mistake kindness for weakness when that is never the case. So do not just be naive and think everyone is inherently good. Be the good you want to see in the world but be the darkness that needs to come when the time calls for it.