For all intents and purposes, former drone operator Brandon Bryant has Kyle beat by a long shot.  According to Bryant, over 1,600 deaths were dealt by him through the technological terror that patrolled the skies of the Middle East for the past decade.  Unlike Kyle, though, Bryant isn't flaunting his skill as a State-sanctioned murderer: he regrets it.  For six years, he flew the missions on orders from on high.  Now he's retired from it and is speaking out.  Bryant was diagnosed with PTSD shortly after leaving the program, odd only because normal diagnoses involve situations of prolonged mortal terror.  Air Force psychologists have referred to conditions similar to Bryant's as "existential conflict", or "moral injury".

Engaging in constant behavior that directly violates one's own moral norms results in this "moral injury", a term used by Dr. Jonathan Shay in his book, Achilles in Vietnam: Combat Trauma and the Undoing of Character.  The Foreign Policy piece linked to quotes Dr. Brett Litz on the distinctness of moral injury from PTSD: "perpetrating, failing to prevent, bearing witness to, or learning about acts that transgress deeply held moral beliefs and expectations."