Special Officer Russell Adler is the deuteragonist to antagonist featured in Call of Duty: Black Ops Cold War. He is a CIA agent charged with stopping the mysterious Soviet agent codenamed Perseus. Adler is described as "America's monster" with a "dark charisma". He later serves as the protagonist of the post-launch seasonal narrative for Black Ops Cold War, going up against Vikhor "Stitch" Kuzmin.
Adler is also a playable Operator of the NATO faction in Black Ops Cold War and Call of Duty: Warzone.