Which Assassin's Creed title was the first to let players control two protagonists in its main campaign?

Assassin's Creed Syndicate was the first main Assassin's Creed title to let players control two protagonists in its campaign.

The two protagonists are the twins Jacob Frye and Evie Frye. Players can switch between them during much of the London story, and each has a different specialization: Jacob focuses more on direct combat and gang leadership, while Evie emphasizes stealth and Assassin skills. Some missions are assigned specifically to one twin.

Earlier games featured one primary playable historical protagonist, even when they included multiple timelines, memories, or supporting characters. Syndicate's dual-protagonist structure therefore differs from simple character cameos or short playable flashbacks.

Later games changed the model again. Odyssey offered a choice between Kassandra and Alexios, while Valhalla allowed Eivor to be played with a selectable gender presentation. Those systems are different from Syndicate's simultaneous pair of named protagonists sharing one campaign.