League of Shadows

The League of Shadows was a group of vigilante ninjas led by Ra's al Ghul  in the film Batman Begins and led by Talia al Ghul in The Dark Knight Rises. They are based on the League of Assassins.

Origin
Throughout history, the League of Shadows was a secret society that, in their minds, restored balance to places where the environment was affected by human corruption. Some of their activities were the sacking of Rome, starting the Black Plague, and the great London fire. Whether Ra's al Ghul was always the leader due to the life-restoring Lazarus Pit (as in the comics) is unknown. An ancient and powerful organization, the League was based on a mountain in the Himalayas (though other bases around the world may have existed)

The men who have sworn allegiance to Ra's al Ghul and the League of Shadows come from many different backgrounds; former soldiers, mercenaries, assassins, petty criminals and ordinary men. However, all of them share a common similarity in which all desire to find justice and a hunger for vengeance to redress a crime inflicted upon him or his loved ones.

Every member of the League of Shadows are fanatically loyal to Ra's al Ghul and his cause. It is this fanatism in which every Shadow warrior knows that he is expendable, his life forfeit, if it means fulfillment of Ra's al Ghul's ultimate plans. Thirty years before the events of Batman Begins, the League of Shadows and their leader storm an ancient prison to exact revenge over the death of Ra's al Ghul's love. In the process they rescued an inmate, Bane, who aided in the escape of Ra's daughter. Bane was then trained in the arts of the League, that of theatricality and deception, but was excommunicated by Ra's al Ghul for his extreme nature and ferocious tendencies in fighting.

Talia recounted that her father never truly accepted Bane into the League of Shadows, referring to him only as "a monster". Following the death of Ra's al Ghul at the hands of Bruce Wayne, Talia and Bane usurp control over the League of Shadows, in attempting to both subjugate Gotham and bring justice over Ra's death. The League of Shadows, as an unnamed organisation, attracted the attention of the Central Intelligence Agency, in particular their attempts to capture a Russian nuclear physicist Doctor Leonid Pavel. Bane then stages an elaborate scheme with the League of Shadows members to subdue the CIA agents and fake Doctor Pavel's death to detract suspicion from their aims.

Batman Begins
At one time, when Bruce Wayne was but a child, the League attacked Gotham City. Infiltrating its infrastructure and manipulating the economy, it started a depression that was designed to destroy the city. However, the crime that resulted from it brought about the death of Thomas Wayne and his wife. This shocked the people of Gotham, most notably the rich and powerful, into saving the city from the depression.

A number of years later, Bruce himself joined the League to fight injustice. While traveling the globe, he was recruited from a Tibetan prison by a man named Henri Ducard, who saw great potential in the angry young man. After completing his training, he saw what the League really was, and left, destroying their base and the man he believed to be Ra's al Ghul himself. However, he saved Ducard, his teacher while in the League.

Bruce returned to Gotham City and became Batman to fight the city's crime, using Ducard's lessons in the martial arts, stealth, intimidation, and theatricality. Meanwhile, the League was busy bringing a fear toxin (created from a hallucinogenic blue flower grown near their Himalayan base) into Gotham by employing some of Gotham's criminals, most notably Carmine Falcone and The Scarecrow. After Batman put both men behind bars, the League was forced to act sooner than expected. Using a microwave emmiter stolen from Wayne Enterprises, they began vaporizing the city's water supply, which the toxin had infected. Everyone who breathed in the toxin turned on everyone else in fear.

Batman, with the help of James Gordon, was able to stop the League however this couldnt work before it could vaporize all the water in the city. In the process, Batman left Ra's for dead on a train that crashed. Whether he survived is unknown, and the League's current activities, if any, are unknown. Though they may have disbanded with the death of their leader, the League's longevity would indicate that they may one day rise again.

The Dark Knight Rises
The League of Shadows is operated by Bane as its de facto leader with the aim of staging a Communist-style revolution in Gotham City and instituting a state of martial law over it. Bane challenges Batman to a fight in his underground base, wherein he outlines his aims of restarting the League of Shadows to Bruce and fulfilling Ra's Al Ghul's destiny. While Bane was left in charge of the day to day runnings of the League and to amass the army and resources that they would need to begin their revolution, Talia hid in the shadows as Miranda Tate, working to infiltrate the Wayne Enterprises Board of Directors to gain access to their top secret fusion reactor and use it as a bomb.