If you had to point to a moment that embroiled the DC film universe in controversy from the start, before it even was a cinematic universe, it would be the end of Man of Steel. After the massive Battle of Metropolis, which caused damage on an insane scale, Superman was forced to kill General Zod, snapping his neck to save an innocent family from his heat vision. For the big blue boy scout to take a life in this way ran counter to the character's ethos for many fans, as Superman is often defined as a hero who doesn't kill. But for actor Henry Cavill, this act wasn't a violation of Superman's creed, but the catalyst for it, as he explained:
The killing of Zod would have led to a wonderful reason why Superman never kills. Not, he never kills just because his dad said so one day. He made the decision himself because of an impossible scenario, to which he then said, 'I don't care if it's impossible again, I'm gonna find a way to make it possible in the impossible.
As Henry Cavill told Square Mile, he sees the act of killing General Zod in Man of Steel as the event that cements the no-killing rule in Superman's mind. Not some idealistic lesson from his father, but having firsthand experience of what it means to kill someone is the thing that makes him have that rule in the first place. From that moment forward, understanding the ramifications, Superman vows to never do it again. It's from here that he began the transition to the traditional Superman who never kills and is a beacon of hope and good that we all know.
This reasoning does make logical sense within the context of the film. Man of Steel is the origin story of Henry Cavill's Superman. He isn't some seasoned pro, but someone who is just learning who he is, what he's capable of, where he comes from, and who he is supposed to be. Therefore, this is the first time he is ever confronted with having to kill someone.
I'm sure Superman purists may take umbrage with this reasoning and think that Superman's belief in never killing should be innate, and part of his upbringing and who he is. It shouldn't be something that he has to experience to make up his mind about. But being staunchly against something in the abstract versus being faced with it in a real-life situation are two entirely different things.
We see Superman pleading with Zod to stop, we see his anguish as he makes the choice and in the wake of it. He isn't some cold-blooded killer, but someone who was faced with a horrible decision to either kill or let innocents die. There is an argument to be made that to be faithful to the character he shouldn't have been put in such a situation in the film or should have found another way, but personally within the context of the scene as it stands, I saw it as him having no other option.
I'm sure this will be debated forever but hopefully we'll eventually get a Man of Steel 2 to see more of Henry Cavill's Superman and his journey. In the meantime you can check out our guide for all of the latest from DC's movie universe.