League of Assassins founded by Ra's al Ghul
Fictional team history
Under Ebeneezer Darhk's leadership
The League of Assassins was founded by Ra's al Ghul (at 1013 A.D.) to be "the fang that protects the head" (Batgirl #67, 2005). Members of the League demonstrated willingness to die at a word from Ra's. They have included some of the most dangerous assassins in the world including Lady Shiva, David Cain, and Merlyn. For much of its current history, any member who failed in an assassination was in turn targeted by the League. Indeed, one of its best-known members, the master-archer Merlyn, was eventually forced to flee from the League, fearing for his life, having failed to assassinate Batman. In more recent years, this policy has apparently relaxed somewhat.
Ebeneezer Darcel, aka Doctor Darhk, was the first known individual assigned to head the League of Assassins by Ra's al Ghul. Darhk himself was seconded by the Sensei, a martial arts master from Hong Kong. Although many of the League's leaders over the years have been accomplished martial artists, Darhk himself did not depend on physical prowess, and as an assassin he instead relied upon careful planning and manipulation, ambushes and death traps, as well as a variety of cleverly concealed weapons and poisons. Although the League apparently had an inner circle of elite fighters as well as a large number of warriors trained in the martial arts, the League during Darhk's tenure as leader reflected his personal methodology. Following a "falling out" with Ra's (the exact details of which were never made clear) Darhk kidnapped Ra's daughter, Talia al Ghul. Batman became involved in this matter while attempting to bring the League to justice for a number of recent killings. Although he had connected the League to several assassinations over the years, all previous attempts to investigate had met dead-ends. Batman rescued Talia (the first time the two would meet, laying the foundation for all their future interaction) and Darhk died while trying to kill them.Gotham
The League of Shadows first appear in the Gotham episode "Heroes Rise: Destiny Calling." Known members are Ra's al Ghul, Sensei, Anubis, The Hunter, Leila, and Palden. They are revealed to have manipulated the Court of Owls into doing their bidding. Some of its ninjas attacked Fish Mooney, Oswald Cobblepot/Penguin, Hugo Strange, Victor Fries, and Bridgit Pike at a slaughterhouse where Hugo Strange's earlier cures for Alice Tetch's poisonous blood was being held. Most of the ninjas there were killed by Jim Gordon which also ended with Fish Mooney accidentally getting killed. Other ninjas from the League of Assassins were present at the Yuyaun Building when Bruce Wayne first meets Ra's al Ghul. In the episode "A Dark Knight: "One of My Three Soups", the energy that Ra's al Ghul placed in Barbara Kean served as a beacon that called the League of Shadows to her. After the unnamed captain of the League of Shadows (portrayed by Ethan Herschenfeld) doubted Barbara Kean leading them as a female has never led them before, Barbara Kean killed him when he tried to take the title from her. After a brief blackout, the female members (named Sisters of the League) of the League of Shadows led by Leila massacred the weaker members as Barbara plans to make use of the League of Shadows. In the episode "A Dark Knight: To Our Deaths and Beyond", Ra's' loyal followers led by Palden manage to resurrect him. In the episode "A Dark Knight: No Man's Land", the League of Assassins and Jeremiah destroy the bridges out of town, isolating Gotham from the rest of the world. After Gotham City has been evacuated and following Ra's al Ghul's second death, Palden and those with him want to swear their allegiance to Barbara. After Barbara hears from Tabitha about Penguin shooting Butch Gilzean, she states that man is the problem that the world has and has Leila and her female League of Assassins teammates kill Palden and his teammates while using their bodies to establish an all-female territory. In season 5, the Sisters continue to support Barbara following Gotham becoming a No Man's Land. In the episode "Legend of the Dark Knight: I Am Bane", Ra's al Ghul's daughter Nyssa al Ghul arrives to exact revenge on Barbara and Bruce for her father's death while also being the benefactor of Bane's mercenary squad, Delta Force. Nyssa goes to the Sirens Club and kills all of the Sisters for betraying their original leader's goals. Nyssa states the League is "everywhere". This implies there are members stationed around the world despite the deaths of the Sisters and the loyalists.