Which Assassin's Creed game was the first in the series to feature a female lead character?

Assassin's Creed III: Liberation was the first Assassin's Creed game to feature a female lead character.

Liberation stars Aveline de Grandpré, a French-African Assassin operating in eighteenth-century Louisiana. Ubisoft Sofia developed the game, which was originally released for the PlayStation Vita in 2012 alongside Assassin's Creed III. Aveline's story uses the same broad historical period as Assassin's Creed III but follows a separate protagonist and campaign.

Later mainline entries made female protagonists more prominent. Assassin's Creed Syndicate features Evie Frye as one of its two playable leads, while Odyssey lets players choose Kassandra or Alexios, with Kassandra treated as the canonical protagonist in related official material. Valhalla offers Eivor as a customizable protagonist whose default presentation can vary. Those later examples do not change Liberation's earlier place in the series' release history.