Joker (DC Comics)

While the exact details of the creation of the Joker and the man's past before he became the so-called Clown Prince of Crime are sketchy at best, the Joker himself admitting that if he is to have a past, he would prefer it be multiple choice. The accepted version is that he started off as a petty criminal named the Red Hood, who was given his infamous appearance after he ended up taking an acid bath after a confrontation with Batman. This along with the rest of his tragic day, drove him entriely mad, and the Joker was born.

Joker has since become the greatest adversary Batman has ever engaged, and is responsible for many of the greatest crimes to the Bat Family to date. He violently clubed the second Robin, Jason Todd, to death with a crowbar, he kidnapped Barbara Gordon, the original Batgirl and daughter of the GCPD Commissioner Gordon, and shot her in the spine, paralysing here.

Despite his absolute insanity, the Joker is actually a criminal mastermind and genius planner, with an intelect that could easily rival Batman if he could focus it more. He has a penchant for dark and sadistic humor, which often manifests itself in the way he kills his enemies. His relationship with the Batman can be described as obsessive at the least, and is even portrayed occasionally as a twisted homo-erotic need to interact with him. Even when it's not, it's generally accepted that the Joker does in fact, need the Batman and the vigilante is what completes him.