Now, The Joker is a psychopath killer who revels in making Batman's life a living hell. However, after his first appearance - in which he was a killer - the character was changed into someone more interested in stealing fine art and jewellery. That stuck with him until the 70s, and there was even a period before that which saw The Joker become a mockery of Batman, creating his own elaborate gadgets and even bizarre looking Joker themed vehicles. That didn't last for long though as it became clear that a status quo change was desperately needed. "The Joker's Five Way Revenge" was the start of that as the story revolved around the villain deciding to murder five men who had failed him, forcing Batman to step in and protect those he would normally try to take down. It also helped to develop The Joker's relationship with Batman as his obsession and dependence on the hero became clearer.