Which Assassin's Creed game was the first in the series to feature a female protagonist as a selectable main character?

Assassin's Creed Syndicate was the first main series game to feature a female protagonist as a selectable main character.

Syndicate lets players control Evie Frye as well as her twin brother Jacob Frye. Evie is therefore a selectable lead character in a mainline Assassin's Creed release, rather than only a supporting character or a protagonist in a separate spin-off.

Earlier games had already featured important playable women in other forms. Aveline de Grandpré leads Assassin's Creed III: Liberation, a spin-off, and later mainline games such as Odyssey and Valhalla also offer protagonist choices.

The wording matters because games are sometimes grouped differently. Liberation predates Syndicate and has a female lead, but Syndicate is the relevant first main series title with a selectable female protagonist alongside a male option.