Heroes Never Kill... Except...

Everybody knows that Superman and Batman have just one rule: you don't kill. The world's finest heroes have traditionally been more than equipped to find better, non-lethal solutions to even the toughest problems. But as <i>Man of Steel</i> showed, sometimes that line can blur, much to the chagrin of some fans. <p>While <i>Man of Steel</i> may have been outside of actual comic continuity, there have been plenty of examples of both Superman and Batman breaking their chief commandment that were in continuity - at least at the time they were published (because of that, we're leaving out books with their own continuity, like <b>Injustice</b>, to your left). Here are ten of the most prominent examples of both the Man of Steel and the Dark Knight taking a life.

Batman Kills the KGBeast (Batman vol.1 #420, 1988)

The KGBeast was a Russian super-assassin who gave Batman fits by eliminating a number of high-profile Soviet defectors in rapid succession, stymieing Batman's efforts to stop him at every turn. Batman finally caught up to the KGBeast after thwarting an attempt on the life of President Reagan. <p>In their final confrontation, Batman fights KGBeast to a standstill in an underground chamber. With the badly injured KGBeast challenging him to a fight to the death, and with the knowledge that the KGBeast's capture would mean extradition to the Soviets and his freedom, Batman instead pulls a cold-blooded, full-on Fortunato, walling the assassin in an underground chamber and leaving him to die, simply informing the police that they "needn't worry about him anymore." <p>Of course the death was retconned several years later, with Batman noting that he had the police collect the KGBeast later, but the intent of the original tale remains clear.

Superman Kills a Kryptonian Dragon (Superman vol. 3 #13, 2013)

During the "H'el on Earth" saga, in which a mysterious Kryptonian villain attempts to resurrect his long dead homeworld, Superman found himself face to face with a massive dragon of mysterious origins. <p>Battling the dragon furiously, Superman finally senses that the creature is in a state of cellular decay. Knowing the destruction it will inevitably cause, as it is all Superman can do to keep the creature at bay, Superman uses his heat vision on a nearby oil well to cause a massive explosion that decimates the beast. <p>Moments later, Supergirl arrives, informing Superman of the beast's Kryptonian nature, and setting off a chain of events leading to H'el very nearly destroying the Earth. Sure, this one isn't as monumental as others, since it's not a humanoid, and seemed to have been animated in a way outside of conventional thoughts on life, but it's notable for being the first such instance at all in the New 52.

Superman Kills Imperiex and Brainiac (Action Comics vol. 1 #782, 2001)

In the “Our Worlds At War” crossover, a living force of pure entropy known as Imperiex makes its way across the universe towards Earth, decimating and unmaking planets as they crossed his wake. <p>Imperiex was such a huge threat that Earth's heroes formed an alliance with Darkseid and the planet Apokolips as well as Brainiac-13 and his planet-sized battlestation Warworld. In the end, Brainiac betrayed the group, attempting to seize Imperiex's powers for himself. <p>Left with little recourse, Superman pushes the massive Warworld through a boom tube, sending the entire battlestation back in time to the big bang, taking with it Imperiex and Brainiac, and destroying them in the process. Superman justifies this by saying that he can't truly kill either of them, merely "spread their consciousness across trillions of light years instantly." That... that sounds a lot like death, Kal.

Superman Kills a Sun-Eater (Action Comics vol. 1 #847, 2007)

Superman has faced several of the massive, star-snuffing Sun-Eaters throughout his career, but on most of these occasions, it has been others that have done away with the powerful cosmic threats. <p>Told in a flashback, "Intermezzo" recounts the tale of Jonathan Kent's first visit to Superman's Fortress of Solitude. During the visit, Superman builds a small spacecraft out of sunstone, bringing his adoptive father with him on a jaunt through the stars. <p>In the course of their adventure, the pair run across a distress signal from a neighboring galaxy. Leaving Jonathan behind, Superman encounters a Sun-Eater, and the remains of a craft carrying a powerful bomb designed to destroy it. Seeing no other option, Superman carries the bomb into the Sun-Eater himself, saving the star system, and assuring his father's belief that Superman can overcome any odds.

Batman Kills Numerous Gangsters (Detective Comics vol. 1, various issues)

In the late '30's and early '40's, before a changing demographic and public outcry caused superhero comics to take a decidedly more PG rated turn, Batman was hardly the pinnacle of non-lethal justice he is now. <p>In his early days, Batman was a gun-toting vigilante given to ending a criminal's life almost as easily as his career. Though he was hardly on the level of a character like the Punisher, for a while Batman was killing gangsters like it was his job. <p>Many of these weren't just straightforward killings, either. Batman did his fare share of shootings, but he also hanged criminals off his Bat-Plane, defenestrated them, impaled them on swords, and crushed them under their cars.

Batman Kills Darkseid (Final Crisis #6, 2009)

Non-lethality may be seen as Batman's one rule, but the Caped Crusader abides by a strict code that dictates his behavior at all times. Chief among his personal beliefs is that he will never use firearms, seeing in them only the destructive force that killed his parents. <p>However, when the mad God Darkseid conquered the Earth with the power of Anti-Life, Batman saw fit to go against his own code, and using a special bullet designed by Darkseid to kill other Gods, fires a single shot into Darkseid's torso. In his final moments, Darkseid unleashes the power of his Omega Sanction, seemingly vaporizing Batman, leaving only a smoldering skeleton behind. <p>Finishing the job that Batman started, two Flashes, Wally West and the newly resurrected Barry Allen rocketed around the globe at top speed, vibrating through Darkseid's body just as the Black Racer, God of death, came to claim Darkseid's soul.

Superman Kills Doomsday (Superman vol. 2 #75, 1993)

Long ago, in the time just before the so-called "speculation boom" of the '90's, it was not commonplace to have major characters die in their stories. It was even less common for them to return from the dead. When Superman did both, the resulting story became an instant classic, and remains one of the best selling comic book stories of all time. <p>In the story, a Kryptonian monster known as Doomsday arrives on Earth, and after first decimating the Justice League, moves on to a series of confrontations with Superman. In their final battle, Superman and Doomsday lay into each other full force, with Superman holding nothing back. As their blows cause shockwaves and tremors that shake Metropolis, the pair finally cease fighting as they both fall dead at each others' hands. <p>Of course both Superman and Doomsday would later return, but Superman's death, while it lasted, was as momentous an event as had ever been seen in comics. To save the Earth, Superman took the ultimate action, and in doing so, paid the ultimate price.

Batman Kills the Mad Monk (Detective Comics vol. 1 #32, 1939)

The Mad Monk was one of Batman's earliest nemeses, appearing just a few issues after Batman himself. The Monk was a powerful sorcerer, displaying hypnotic and vampiric abilities, as well as all out lycanthropy. <p>Knowing that the Monk's abilities make him far too powerful to take out head on, Batman sneaks into his manor while the Monk sleeps. Despite the fact that this was well before Batman had developed any compunctions against killing - or against the use of guns, for that matter - Batman's defeat of the Mad Monk was one of his most brutal killings yet. <p>Creeping up on the sleeping Monk and his accomplice Dala, Batman kills them both by shooting them with silver bullets made from candlesticks found in the Monk's own lair.

Superman Kills Zod & the Phantom Zone Criminals (Superman vol. 2 #22, 1988)

When DC Comics rebooted its universe in the early '80's, it's biggest relaunch was Superman, helmed by John Byrne. As part of this reboot, a decree was passed that Superman was the one and only survivor of Krypton, rendering the various other survivors introduced throughout his history obsolete. <p>Of course, this didn't stop creative writers from finding new ways to introduce and explain those characters. After venturing into a "pocket universe" where many Kryptonians had survived the planet's destruction, Superman battles this universe's Zod, and his accomplices Quex-Ul and Zaora. After their defeat, Superman decides he must carry out the death sentence passed on them before Krypton's destruction. <p>Using a portion of the pocket universe's green Kryptonite - to which Superman, being from a different reality, was immune - Superman executes the three Phantom Zone criminals before returning to his home dimension. This was hardly the first time Superman had seemingly killed Zod, but it remains the most prominent and least ambiguous example in comics, and the precedent by which Man of Steel abides.

Batman Kills the Joker (The Killing Joke, 1988)

OK, this one may be ambiguous - it's based on theories put forth by creators who both worked on the book, and those some may simply consider scholars - but if it's accurate, it's easily the most important example on this list. <p>In The Killing Joke, the Joker captures Batman's ally Commissioner Gordon, and shoots and tortures his daughter Barbara, culminating in her paralysis and retirement from her alter-ego, Batgirl. Tracking the Joker to an abandoned amusement park, Batman frees Gordon who urges Batman to take Joker down by the book. Making his way through Joker's deadly funhouse, Batman finally confronts Joker, offering to get him the help he needs to begin moving past his insanity. Joker declines, reciting a bizarre joke. In the final scene of the book, Batman is shown in silhouette, gripping the Joker as they both laugh maniacally. The laughter abruptly ends, followed by the lights of the room they occupy dimming, as if Batman is leaving the scene. <p>While ambiguous, there is a strong theory that in this finally scene, Batman finally kills the Joker, realizing that there is no end in sight to their twisted rivalry. Though the Joker's later appearances seem to discredit this entirely, several creators including the book's artist, Brian Bolland, and longtime Batman writer Grant Morrison have posited that it was writer Alan Moore's original intent that the scene marked the final confrontation between Batman and the Joker. Moore remains mum on the topic, though his original script lends little evidence either way.

WORLD'S DEADLIEST: 10 Times Batman and Superman Have Killed Their Enemies

Date: 18 December 2013 Time: 09:00 PM ET