Bane is the arch-nemesis of the new Batman movie The Dark Knight Rises. Many casual Batman fans, however, haven't heard of him before.
Among Batman villains, Bane is indeed less prominent than The Joker, The Penguin, Mr. Freeze, and Two-Face. But to serious comic book fans, Bane is seen as a highly intriguing villain and one of the Dark Knight's most successful foes.
He has the distinction of being the only one to break the back of Batman, or to have Broken the Bat, in a mid-'90s series. In fact, whether or not Batman's back will be broken by Bane is a subject of intense speculation among fans of the Dark Knight movie series.
Unlike most villains, Bane is highly intelligent and almost noble. He's not motivated by insanity or base criminal desires like The Joker or The Penguin. Instead, he's a purist who is out to prove himself and search for meaning in life.
Bane inherited his refugee father's sentence and grew up in prison under a (fictional) corrupt government. In that gritty environment, he trained himself both mentality and physically. His hardiness got him noticed by government officials, who then used him as a test subject for a drug called Venom.
It is this drug that gives him super strength in addition to his naturally acquired cunning and fighting skills.
Bane escaped from prison and eventually became obsessed with Batman, who he saw as a worthy opponent to destroy. He approached his Batman conquest methodically.
He first broke out the criminals of Gotham City and tired Batman out with the task of putting them back in prison. When Batman finally returned to his citizen residence of Wayne Manor, he was exhausted.
It was then that Bane struck and overcame the weakened Bruce Wayne and broke his back.
Subsequently, Bane drifted between being a villain and hero. He even collaborated with Batman at times. Much of his actions were motivated by his quest to search for his father and find his own identity.