No villain has been more persistent in his attacks onBatmanthan theJoker. Every other villain will either retire or give up on their goals. But the Joker has been shown to constantly evolve with Batman; no matter what Batman does, the Joker is still there, matching him every step of the way. I truly think that this means, eventually, that the Joker will end up defeating Batman, and there are tons of stories in the DC Universe that support this theory.
It’s no secret that Batman is getting older.Batmanhas been fighting crime in Gotham for decades at this point. It’s only natural that he’d get older and that he’d start to slow down. Because of this,Batman is considering a serum that restores his youth, as seen inDetective Comics#1091 by Tom Taylor, Mikel Janín, and Wes Abbott.

This new “immortality” serum would make it much easier for Batman to fight crime and protect Gotham City for as long as possible, but I think thatthere’s a major negative consequence that Batman hasn’t thought of yet,and it involves the Joker living forever alongside him.
DC Has Implied that the Joker Will Live as Long as Batman Does - If Not Longer
If Batman Doesn’t Retire, the Joker Will Kill Him
The Joker is obsessed with Batman. If Batman finds a way to stop his aging, thenthere’s no reason to think that the Joker won’t find a similar way to extend his own lifeso that their battle can continue forever. The most concerning thing about Batman accepting this youth serum is that he hasn’t considered how the Joker will react to it. Batman has agonized over whether he should accept the serum or not, even talking to Superman, who ultimately convinces him to do it. But that Batman never even considered how the Joker would respond to this means that Batman doesn’t understand one fundamental aspect of his biggest villain.
DC has published many stories that show thatwhen Bruce Wayne stops being Batman, then so too does Joker stop being a villain. One of the most important of these stories isBatman: Going Saneby J.M. DeMatteis and Joe Staton. The same is true in the story ofThe Dark Knight Returnsby Frank Miller. In the former, the Joker immediately gives up his violent ways and becomes a normal law-abiding citizen of Gotham after he believes that he’s killed Batman. In the latter, once Batman retires, the Joker goes into a catatonic state, only becoming active again when Batman’s return is reported on the news.

Now that Batman has ensured that he will never retire, the only option left is Batman’s death.
Both of these situations are a definitive end to thebattle between Batman and the Joker. But now that Batman has ensured, inDetective Comics, that he will never retire, the only option left is Batman’s death. I know it might be hard to believe that the Joker will defeat Batman, especially after the decades worth of victories that Batman has over him, butthere are so many stories that state that, given enough time, the Joker will definitely kill Batman.It isn’t just across alternate universes either, as even certain future stories have shown that the Joker will often outlive Batman.

Eventually, the Joker Always Seems to Kill Batman
Is Batman’s Fate Really Set in Stone?
There are several timelines where the Joker ultimately kills Batman. A few alternate universes are the origin ofThe Batman Who Laughs in the Dark Multiverse. Here, the Joker decides to launch one final attack on Batman,succeeding in killing most of Batman’s alliesand transforming Batman into a new Joker.
Another example is inCatwoman: Lonely Cityby Cliff Chiang, whereinthe Joker and Batman’s final battle comes to be known as Fool’s Night, which is the night that Batman dies. Knowing Batman would always choose to save a life over anything else, theJoker tricks Batman into killing James Gordon, and when Batman tries to take revenge, the Joker kills them both with a bomb vest.

The Joker’s Most Iconic Cover Comes to Life in a Chilling Killing Joke Cosplay
The Killing Joke is a seminal DC Comics story, with a new cosplay design expertly bringing one of the comic’s most iconic images into the real world.
There are so many examples that showBatman and the Joker’s feud can only end one of two ways. Either Batman retires and the Joker quits as well, or the Joker will eventually evolve to a point where he kills Batman. Now that Batman has taken a serum that gives him eternal youth, it’s unlikely that he’ll ever retire, which means that he’s simply guaranteed his own death. I honestly think that it’s surprising that Batman, the world’s greatest detective, didn’t take into consideration the behavior of his biggest villain before making this crucial choice.

The Joker Will Never Stop Fighting Batman
Never the End - At Least for These Two Iconic Characters
Having to constantly consider the Joker isn’t the greatest thing, but as Batman refuses to kill him, making this choice without considering the Joker’s reaction is an absurdly dangerous mistake. Batman and the Joker have been fighting for decades, and the Joker has only continued to grow more and more dangerous. While some fans might think that the Joker will simply get old and be unable to keep up with a forever-young Batman, there have been plenty of universes and timelines where the Joker has managed to prolong his life, such asBatman Beyond. I really don’t doubt that, with this serum,Batmanis destined to be killed by theJoker.
The Joker
The Joker is a psychopathic criminal mastermind with a warped sense of humor. Initially introduced as a remorseless serial killer, the character evolved over time, often oscillating between a prankster and a homicidal maniac. His relationship with Batman is one of the most complex in comic book history, defined by their mutual obsession. Over the decades, the Joker has become an enduring icon of chaos and madness, embodying the antithesis of Batman’s order and justice.
Batman
One of DC’s most iconic heroes, Batman is the vigilante superhero persona of billionaire Bruce Wayne. Forged by tragedy with the death of his parents, Bruce dedicated his life to becoming the world’s leading martial artist, detective, and tactician. Recruiting an entire family of allies and sidekicks, Bruce wages war on evil as the dark knight of his hometown, Gotham City.
