Created by Bill Finger, Jerry Robinson and Bob Kane all the way back in the first issue of Batman in April 1940, The Joker is a character that has grown to become not only one of the most influential comic book characters of all time, but a true cinematic powerhouse too.
Intended to be killed off for good after his debut, DC editors perhaps made the best decision of their history by realising the potential the character had as the perfect adversary for their stone-faced and justice-driven Caped Crusader.
The Joker and Batman are designed to be polar opposites of each other, something the Clown Prince of Crime delights in exploiting over the course of their showdowns, but underneath their constant (and sometimes fatal) duels, a certain reliance on the other has been shown to exist between the two.
The Joker acknowledges this reality much more than Bats, but both have acknowledged in the past that they struggle to exist without the other in their lives.
With that in mind, here are ten examples of The Joker going out of his way to save Batman and keep their games of cat and mouse going.
10. Protecting Batman's Secret Identity
The Joker undoubtedly revels in the dynamics between himself and Batman and the games they have played over the years, so there might admittedly be a case of selfish motivations at work for the Clown Prince of Crime to keep the Batman in Gotham for as long as he can.
Only a handful of characters in the DC Universe know of Batman's hidden identity as the multi-millionaire businessman Bruce Wayne, and even the likes of the Riddler have struggled to even believe it to be true when presented with the fact. The Joker, on the other hand, is one of the few characters shown to be all too aware of Bruce Wayne's alter-ego.
Batman #663 sees the Joker playfully taunting Bruce Wayne about his identity, and Batman Beyond: Return of the Joker shows how DC's biggest baddie has all the means to gain all the information he needs.
Time and time again, the Joker has never stooped to using his greatest weapon of all against his oldest enemy, and has even gone out of his way to deflect things away from his goons at times. The Joker is absolutely enamoured with the idea of Batman, not the man himself, and there's a strong sense that he genuinely struggles with the idea that the Dark Knight could ever be stripped down to just being a man.