Ask the general public what the most famous or scariest Batman villain is, and nine out of ten times you’ll hear “The Joker.” The Joker, or Jack Napier, is a madman. He is a representation of all things unhinged, random, and immoral. He is perhaps a Batman villain that terrifies many people on an individual level. In the comics, however, Batman has always had one villain that dwarfs all of the others in terms of terror. This villain is known as The Batman Who Laughs. The Batman Who Laughs has terrorized Batman and the DC universe with his presence, and rightfully so. The Batman Who Laughs is probably the Batman villain that most terrifies people in terms of just reading about him and what he’s done.
A Dark Reflection
He's more than just another Joker on Batman's list of enemies. The Batman Who Laughs is a "dark reflection" of the Dark Knight. A version of Bruce Wayne from Earth-22 of the Dark Multiverse, he was subjected to the Joker-like toxin, but instead of erasing his personality, it also removed all of his sense of right and wrong. The Batman Who Laughs still has the acumen, intellect, and deductive reasoning of Batman, but he also has the power, agility, and adaptability of a well-trained superhero. But most importantly, he has no morals or sense of morality, and because of that, his fellow Bats won't be able to make him hesitate, not even for a second.
Like the Joker, The Batman Who Laughs does enjoy the act of causing pain, of making people suffer. He just goes about it in a much more efficient, more tactical way. He knows Gotham inside and out, and he's used his knowledge to bring fear and suffering to the place that made Batman and used his power to target those closest to him: Batman's allies and family. Like when he psychologically and mentally tortured Tim Drake into revealing all of Batman's secrets. But perhaps the most disturbing act was when he made a Joker of Damian Wayne, Batman's own son.
This twisted incarnation of Batman first appeared in the Dark Nights: Metal crossover. But when he did, it was clear that DC had a hit on their hands, creating one of the smartest, most brutal, and deadliest Batman villains to ever do battle with the Dark Knight. Not only does he have all of Batman's knowledge, he also intimately knows the weaknesses of every character associated with Batman in the regular DCU, which is why he's not just a foe, but a villain that stalks Gotham from the shadows as an "insider."
Cosmic Ambition
However, aside from all of this, The Batman Who Laughs is also simply operating on a level much higher than other Batman villains. Batman villains are known to have city-level or Earth-level threats. The Batman Who Laughs, however, has already joined with multiversal beings, such as Perpetua and Barbatos, as one of their right-hand men in their cosmic-level plan to reshape entire realities. Batman Who Laughs has harvested the minds of alternate Batmen, has been able to access the power of Doctor Manhattan through an alternate who has fused with a Bruce Wayne, whom the character has codenamed “Batmanhattan,” and can seemingly do anything he wants to do. He has a level of intelligence that is over-the-top compared to Batman himself, but is also capable of making threats and doing things that are just beyond the concept of a Gotham-level villain. All of this put together is what ultimately makes him more of a threat in comparison to other Batman villains.
His ability to survive and continue to plague the DC universe long after his defeat also makes him much more dangerous than other Batman villains. Even when defeated in battle, Batman Who Laughs' mind and presence are often preserved and carried out by other Dark Knights. He is relentless and horrifyingly self-replicating, unlike the Joker, who can often be reasoned with. In comparison to the Joker, The Batman Who Laughs is a "what if" situation in which Batman's skills of intelligence, planning, and human psychology are used against the world.
