Which Assassin's Creed game was the first in the series to feature a playable modern-day character other than Desmond?

Assassin's Creed IV: Black Flag was the first series game to feature a playable modern-day character other than Desmond.

Black Flag introduces an unnamed Abstergo Entertainment employee as the modern-day playable character. This first-person role is distinct from the historical protagonist, Edward Kenway, and from Desmond Miles, whose modern-day story concluded in Assassin's Creed III. The employee explores an Abstergo workplace, accesses genetic memories, and uncovers information while working on a commercial entertainment project based on Animus data.

The change reflects a major shift in the series’ modern-day storytelling. Instead of giving players a named hero with a long personal arc, Black Flag places them inside the world as an employee whose identity is deliberately left open. Later games use other modern-day protagonists, including a researcher in Assassin's Creed Unity and an unnamed employee in Assassin's Creed Syndicate. Black Flag therefore marks the transition after the Desmond era.