Sheep and Sheepdogs
One thing about that "sheep - wolves - sheepdogs" metaphor.
Sheepdogs aren't natural. Sheepdogs imply - no, mean - the existence of a shepherd.
Kyle never hid that - he was a very vocal Christian who insisted that "I'm willing to meet my Creator and answer for every shot that I took." And because of that, he really didn't seem to mind how many people he killed or to look at the war with any empathy. God was on his side.
Or he was on God's. Like the Dominicans of the Spanish Inquisition, he was God's Dog. God's Good Dog.