The League's ranks are composed of highly skilled ninja warriors. They are expertly trained in the arts of unarmed combat, swordsmanship, marksmanship, and killing.
- Ra's al Ghul (Founder and Secret Leader)
- Lady Shiva (Commander/General)
- Silver Monkey (Former Captain/Deceased)
- Katana (Former/Infiltrator)
- The League is an ancient order of mercenaries who answer to no one but their Master, Ra's al Ghul.
- They're the main antagonist in the first half of season 1.
- They are also called the League of Shadows.
- The League of Assassins is the original name of them from 1968 comics of Batman.
- They will be under command of Talia al Ghul in season 2.
- Their target in the original comics is serum of Dr. Langstorm, not the Ion Cortex.
- The mutant ninjas are voiced by Dee Bradley Baker, who has voiced lots of roles in the previous tv series Batman the brave and the bold.
- The short term to refers the organization is the League.
- In Young Justice, it is the way how the Justice League is being refer to.
1. First appearance of League of Assassins was in the episode Safe when the Dr. Jason Burr created the project "Cortex." League tried to kidnap him but Katana and Batman stop them. When ninjas returned on their base, they told their master that the mission failed. Their leader, Silver Monkey didn't like it, and he decided to take the best squad of ninjas and go to the Wayne Manor, as they knew that Dr. Jason Burr was taken there.
2. They appearanced in the episode Family, when Silver Monkey captured Batman and Katana in the Wayne Manor, and he's got the soultaker sword. When Silver Monkey was close to his victory, suddenly Lady Shiva, when she knew that Silver Monkey tried to direct the League of Assassins against her. When all ninjas of League heard it, they became on the side of Lady Shiva, as she said that League of Assassins ninjas fear Lady Shiva more, than they fear Silver Monkey.
3. In Sacrifice, Lady Shiva makes a deal to retrieve the Calibosix for Anarky in exchange for an intercepted package. Lady Shiva and two ninjas infiltrate a science building which holds the carbox. When they find it however, Batman and Katana chase after them. Soon, Lady Shiva's ninjas get their hands on the Calibosix, but suddenly the Calibosixx is unleashed. This turns them into huge, hulking superhumans and they try to kill Batman, Katana, and Lady Shiva.