Since his debut in Batman #1 in 1940, the Joker has been considered one of the best villains in comic book history. In many of his earliest appearances, the Joker killed dozens of people with his trademark Joker toxin, but soon became a sillier character who rarely used lethal force. The character, much like DC Comics overall, would undergo many tonal shifts throughout the Silver and Bronze Ages.

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What type of villain the Joker is depends on the writer and artist working on him. Creative teams have explored many iterations of the Joker, both in the main DC continuity and stories set in alternate worlds. These versions have only proven the Joker is an incredible, malleable character who can take on just about any form the creators need him to.

10 Martha Wayne Became The Joker In Flashpoint

Martha Wayne Joker Batman Flashpoint

In an attempt to save his mother's life, Barry Allen went back in time and inadvertently created an alternate universe known as Flashpoint. In the Flashpoint universe, Joe Chill murdered the young Bruce Wayne instead of his parents. Thomas Wayne vengefully sought and murdered Chill while Martha suffered a mental breakdown.

In this universe, Thomas became a more aggressive version of Batman who used guns, while Martha, in an effort to smile through her pain, became the Joker. The idea of Bruce's parents mirroring his conflict with the Joker was fascinating and provided one of the most interesting iterations of the Waynes.

9 Speeding Bullets Introduced A Luthor/Joker Hybrid

Lex Luthor becomes the Joker in DC Comics

Superman: Speeding Bullets, written by J.M. DeMatteis and illustrated by Eduardo Barreto, explored an alternate universe where Thomas and Martha Wayne discovered baby Ka-El. After the death of his parents, this Bruce Wayne grew up to become Batman as well, only this time, he had Kryptonian powers.

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DeMatteis and Barreto created an intriguing hybrid of Superman and Batman, but they also fused their main antagonists. The Lex Luthor of this world fell into a vat of chemicals and became the Joker. He had the fused appearance of Luthor and the Joker, which was slightly unsettling, and was certainly a unique take on the Clown Prince of Crime.

8 Emperor Joker Possessed The Powers Of A God

Joker steals Mr. Mxyzptlk's powers DC Comics

Mr. Mxyzptlk, a strange being from the fifth dimension, would often torment Superman by manipulating reality, usually in fairly harmless ways. Superman would easily trick Mxyzptlk and send him back to his home dimension. In Superman vol. 2 #160, Mxyzptlk intended to gift the Joker 1% of his power, but the Joker tricked him and received the other 99%.

The Joker wielded the power to warp reality, but his alterations were far more harmful than anything Mxyzptlk had done. The Joker made everything and everyone more like himself, and he tortured Batman by repeatedly killing and resurrecting him. It took the combined might of Superman, Mxyzptlk, and the Spectre to stop this god-like Joker.

7 The Joker Was Batman's Last Companion On Earth

Batman carries Joker's head in a lantern

Writer Scott Snyder and artist Greg Capullo created some of the best Batman stories ever during their run on the New 52 Batman series. They continued their good work on the character in several limited series like Dark Nights: Metal and Death Metal.

One limited series, titled Batman: Last Knight on Earth, explored a potential dark future of the DC universe. Batman wakes up in a dystopian world and his only companion appears to be the head of Joker inside a glass lantern. The image of Batman carrying the Joker's head is striking and memorable. Last Knight on Earth explores the relationship and reluctant partnership between Batman and the Joker.

6 Frank Miller's Joker Was Twisted & Terrifying

Joker from The Dark Knight Returns - DC Comics

Frank Miller took many classic Batman characters to narrative extremes in The Dark Knight Returns, including its subsequent sequels and prequels. Batman was brutal and his relationships with his old protégés left them feeling resentful and even vengeful.

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The Joker of Miller's universe was more villainous and malevolent than previous versions. He took pleasure in killing Jason Todd and walked around with a cold demeanor. The Dark Knight Returns examined the binding relationship between Batman and the Joker in interesting ways. After Batman retired, the Joker fell into a catatonic state, but when Batman returned, so did the Joker.

5 Greg Capullo Made The Joker Even More Unsettling

Joker dresses as a Mechanic in DC Comics

The Joker made his New 52 debut in the pages of Tony Daniel's Detective Comics series, where the skin of his face was removed. When the Joker resurfaced in Scott Snyder's Batman series, artist Greg Capullo drew one of the creepiest versions of the Joker.

The Joker reattached the skin of his face but arranged it so it looked as though he was perpetually smiling. During the "Death of the Family" arc, the Joker attempted to prove that Batman didn't need sidekicks. Instead, the Joker was all Batman needed. This arc encapsulated why the Joker's symbiotic relationship with Batman is so important to both characters.

4 The Joker Destroyed Superman's World In Injustice

Superman Kills The Joker In Injustice: God's Among Us

The Joker played a huge role in the Injustice universe. While he only physically appears at the beginning of the comic book, the Joker's presence can be felt throughout the entire series. Superman became a tyrant who dominated the world in a misguided attempt to save it, and it was all Joker's fault.

The Joker infected Superman with a fear toxin to make him believe Lois Lane was actually Doomsday. Superman killed her, and when her heart stopped, it triggered a nuclear explosion that destroyed Metropolis. Enraged, Superman brutally murdered the Joker in front of Batman.

3 Brian Azzarello's Joker Was Gritty & Unnerving

Joker shows off his damaged hand

Many of Batman's greatest comic book stories actually revolve around the Joker. If they're not about the Joker, like The Killing Joke, then they explore the effects of his crimes, like "A Death in the Family." Brian Azzarello and Lee Bermejo presented one of the most disturbing versions of the Joker in the 2008 graphic novel, Joker.

A criminal named Jonny Frost picks up the Joker, released from Arkham, and helps him exact revenge on criminal competitors like Two-Face and the Riddler. Throughout the story, the Joker commits some of the most graphic, criminal acts depicted in comics. Bermejo's gritty, realistic art emphasizes this Joker's aggressive, homicidal nature.

2 The Joker Became Gotham's White Knight

Jack Napier turns into the Joker - DC Comics

Batman: White Knight presented a never-before-seen alternate universe where Batman developed brutal methods of serving justice, and where the Joker regained his sanity. Sean Murphy's creation has since exploded into spin-off series like Curse of the White Knight and Beyond the White Knight.

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Murphy's White Knight presented a Joker fans could actually root for. Harley Quinn worked hard to rehabilitate the Joker and prove how Batman was the true villain. White Knight's Joker is one of the most complex, sympathetic versions of the character. Thankfully, with the ongoing success of the Murphyverse, fans haven't seen the last of this Joker.

1 The Killing Joke Explored The Joker Like Never Before

Batman laughs with the Joker in DC Comics

The 1988 graphic novel The Killing Joke, written by Alan Moore and illustrated by Brian Bolland, delved deep into the Joker's character and origins in a way no book had before. Many have cited that the Joker is an unreliable narrator, so anything seen in flashbacks could simply be fabricated, but the origin shown in The Killing Joke is very much confirmed in Geoff John's Three Jokers limited series.

The Killing Joke is dark and extremely graphic, but it's considered one of the best comic stories of all time because of the way Moore developed the Joker's character. The Joker is somehow both a sympathetic victim and a cruel villain who commits the most heinous acts.