"Nikolai" (Russian: Николай) is the code name of a Russian informant amongst Imran Zakhaev's Ultranationalists, and an ally of the SAS in Call of Duty 4: Modern Warfare and Call of Duty: Modern Warfare Remastered. He continues to help MacTavish and Price in Call of Duty: Modern Warfare 2 and Call of Duty: Modern Warfare 3. His real birth name has not yet been revealed.