10 Comic Heroes Who Killed Their Biggest Rival

Generally, when people raise the age-old question of 'why doesn't Batman just kill the Joker?' it's worth reminding them that, in many timelines, he actually has.

While the most iconic case of this has to be in the Injustice series - where he dramatically snaps the clown's neck after the villain killed Lois Lane - this isn't the only time the Dark Knight has decided to off the purple-and-green menace. One of the most interesting new examples of this comes in the recent Dark Nights: Batman Who Laughs tie-in comic, as it suggests that many of the evil Batmen are in fact created when they kill the Joker.

Interestingly, it's revealed that this is the backstory of the Batman Who Laughs himself, as the villain was created by being exposed to a toxin that released from the Joker upon his death. With this in mind, it seems as though the reason that Batman has never killed his nemesis - aside from all those pesky morals - is that he's now seen just how badly things would go for him if he ever were to cave in.