The Real Reason Batman Has A No-Killing Rule

Batman has a strict no-killing rule, as he refuses to take out even the most hardened criminals and evildoers. While the rule is a noble pursuit, allies like Jason Todd question it, believing the Dark Knight allowing his villains to survive ultimately allows them to continue their dark pursuits, causing more problems than if they were put down. The no-kill rule has a very particular reason for existing tied back to his earliest adventures with DC Comics.

In "Detective Comics" #27 by (Bill Finger, Bob Kane, and Vincent Sullivan), Batman makes his comic book debut. In the issue, Batman kicks a villain into a drum of acid, killing him. Batman continues to kill in the earliest adventures of "Detective Comics," leading into his own solo title in "Batman" #1 where, after catching a criminal, he tightens a rope around his neck and hangs him as he glides across the sky. Beginning a few issues later, DC's editorial team implemented a no-kill rule for the hero, frightened of the panic around violence in comic books, writing to staffers, "Heroes should never kill a villain, no matter the depths of his villainy." 

In "Batman" #4, as Batman and Robin fight a group of sword-wielding swashbucklers, the Caped Crusader tells his crime-fighting partner that killing is completely off the table, saying, "Use only the flat of your sword, Robin! Remember we never kill with weapons of any kind!" The comments are a stark contrast from Batman's killer ways early in his career, but with the new mandate, a new era began for the hero — but it wouldn't be the last time Batman killed someone on the page.

Batman killing has largely been left open to interpretation in the main comic book canon. In "Batman" Annual 8 (by Mike W. Barr, Trevor von Eeden, Lynn Varley, and John Costanza), Batman seemingly kills Ra's al Ghul by tampering with an escape shuttle and sending into to his death. In "Batman" #420 (by Jim Starlin, Jim Aparo, Mike DeCarlo, Adrienne Roy, and Costanza), Batman leaves KGBeast in a flooding room in the sewers, suggesting he lets the villain drown. 

The iconic "Batman: The Killing Joke" (by Alan Moore, Brian Bolland, Richard Starkings, and John Higgins) implies Batman ends the Joker's life. The common denominator in all of those stories? Readers don't see the villain die, even if their death appears assured. The rare time Batman visibly kills someone on the page in canon such as "Final Crisis," (by Grand Morrison, J.G. Jones, and Carlos Pacheco) it's to save the universe from major threats, such as Darkseid, where he has no other choice.

In the many Batman films, the treatment of the rule is much different as the hero has a notable kill count. In Christopher Nolan's "Dark Knight Trilogy," Batman (Christian Bale) kills Harvey Dent (Aaron Eckhart) and Talia al Ghul (Marion Cotillard) in high-pressure moments where lives are on the line. Michael Keaton's Batman famously kills a henchman in some incredibly brutal ways. But perhaps most notably, Ben Affleck's Batman from "Batman v. Superman: Dawn of Justice" doesn't seem to adhere to the rule, with director Zack Snyder defending his murderous version of the Dark Knight. But even with Snyder's more open dismissal of the no-kill rule, most live-action Batman at some point have killed somebody.