In "Call of Duty: Black Ops II," Alex Mason is the main playable character in the 1980s missions. Those missions continue the story of the original Black Ops and follow Mason’s return to covert operations during the final years of the First Cold War.
The 1980s storyline takes place primarily from 1986 to 1989. Mason works with his former teammate Frank Woods and handler Jason Hudson while pursuing Nicaraguan arms dealer Raul Menendez. The missions move through conflicts and political crises in places including Angola, Afghanistan, Nicaragua and Panama.
The game’s other major timeline is set in 2025. There, the player controls David Mason, Alex’s son, who is known by the callsign Section. This split is the main reason the answer can be confused: David is the central playable character in the futuristic missions, but Alex is the protagonist of the 1980s campaign.
Black Ops II uses branching choices and multiple endings, but the identity of the 1980s playable character remains Alex Mason.