The League of Assassins is a secretive international criminal organization consisting of highly trained warriors.
In "Safe", the League makes its presence felt in Gotham City as the Wayne Industries project of the Ion Cortex attracted its attention. Lady Shiva sent Silver Monkey and another group of ninjas in a second attempt to attempt to capture Dr. Jason Burr, but was repeatedly thwarted by the Batman and Katana.
In "Family", Silver Monkey plotted to displace Lady Shiva in the League by retaking the Soultaker Sword but the League members remained loyal to Lady Shiva. He was taken away to be punished and Lady Shiva took the sword for herself.
In "Control", in another attempt to capture Dr. Burr and the knowledge for the Ion Cortex, the League sends Cypher on a solo mission in Gotham which results in Dr. Burr being personally affected by Cypher.
In "Sacrifice", Lady Shiva struck a deal with Anarky to return their cargo that he stole from them—cargo that is later revealed to be the body of the League's master, Ra's al Ghul.
In "Instinct," Lady Shiva welcomes Dr. Burr to the League of Assassins.