Forming of the group
After understanding that the energy that Ra's al Ghul placed in her is a beacon to summon the rest of the League of Shadows to Gotham City, Barbara is confronted by it's members. One League of Shadows captain doubts that a woman can hold the title of "Ra's al Ghul" and tries to take it from her only for Barbara to kill him. When Barbara asks if they would still be loyal to her, most of it's members bow to her. Just then, the lights go off and gunfires are heard. When the lights come back on, the female members of the League of Shadows are revealed to have killed off the weaker ones as they pledge their loyalty to her.
Lelia and the Sisters of the League take Barbara and Tabitha Galavan to one of the League of Shadows' hideouts where only Barbara is allowed into the vault. She sees a portrait of what looks like Ra's al Ghul and Barbara Kean causing her to accept her destiny. When Tabitha later comments about this and asks how this will affect their business, Barbara ends her partnership with Tabitha and has Leila and the Sisters of the League remove her. Outside, they beat up Tabitha as Leila states that they will kill her next time.
During the aftermath of Ra's al Ghul's resurrection, the Sisters plead their loyalty to Barbara Kean, after facing Ra's and defending the league, separating themselves from Ra's and allowing Barbara to be there leader without the powers of The Demons Head.
No Man's Land
During No Man's Land, the Sisters of the League still served Barbara and were the guards of the Sirens Club. They aided Barbara in capturing Edward Nygma and interrogating him. The Sirens Club was later attacked by Nyssa, massacring a good number of the people inside. It was unknown however how many of them were members of the Sisters of the League if at all.