The League of Assassins (sometimes known as the League of Shadows or Society of Shadows in adapted works) is a group of supervillains appearing in American comic books published by DC Comics. The group is depicted as a collective of assassins who work for Ra's al Ghul, an enemy of the superhero Batman. The group appeared in Strange Adventures #215 (December 1968), but did not become officially known as the League of Assassins until Detective Comics #405 (November 1970).

The League of Assassins has been adapted into other media several times, predominantly in animated Batman productions, the live-action Batman film series The Dark Knight Trilogy, the CW TV show Arrow, and the Fox TV show Gotham.

Yasser split from the ancient Order of Assassins in a successor movement. Their followers claim to have annulled and deposed centers of civilizations such as Baghdad, Moscow, and Rome, throughout past generations in their lineage. As a part of The Demon, it's sometimes called "The Demon's Fang" or "Demonfang".

The recruits of the League of Assassins follow a strict regimen, carrying distinct black emblems and supplies up to their mountain lairs.

These new recruits are called Ghuls, because they emerge after proclaiming their final prayers in their own prefabricated graves before initiating in various, assigned operations.

Unlike the ancient Order of the Assassins, whose main objective was to halt sectarian conflicts and wars within the world; the League of Assassins acts as an organization that is a catalyst to the reformation of decadent civilizations around the globe.

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 Darrk, was the first known individual assigned to head the League of Assassins by Ra's al Ghul. Darrk 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, Darrk 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 Darrk's tenure as leader reflected his personal methodology. Following a "falling out" with Ra's (the exact details of which were never made clear) Darrk 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 Darrk died while trying to kill them.