Stranger Things viewers have been left to wonder who is "the American" in the season 3 post-credits scene. The mysterious character is never seen during the post-credits but the mere mention of an American in Russia has sparked debate over who it might be. Stranger Things may have dropped clues for fans hinting at who this potentially new (and probably pivotal) character is and how they got into the hands of the Russians.
The post-credits scene lasts only a few minutes as it takes viewers on a short tour through a prison in Kamchatka, Russia. One guard references the American as they walk past a row of cells to collect a different prisoner. There is no visual confirmation on who the American is as well as no verbal confirmation, not even initials indicating a name anywhere on the door to identify who is occupying the American's cell. The mystery over who the American is in the post-credits scene has opened up the door to a few very interesting and very strong possibilities.
The most popular and perhaps most obvious answer is that the American is Jim Hopper (David Harbour). Hopper's body was never recovered from the site where the Russian's machine meant to open the Upside Down gate, and the Russians had plenty of reasons to take Hopper as a prisoner. It's very possible that Hopper is alive but was knocked unconscious by the machine explosion and later taken back to Russian for detainment. Or that he somehow jumped into the Upside Down and was recovered by the Russians. (They do have their own Demogorgon, after all.)
But Hopper isn't the only candidate for the American from the post-credits scene. Since we don't know when exactly this scene is taking place, it's possible these events could have happened before season 3. If that's the case, private eye and conspiracy theorist Murray Bauman (Brett Gelman) should be looked at. Murray is fluent in Russian and is asked to translate for Russian scientist Alexei (Alec Utgotff) by Hopper. Murray's proficiency in Russian is a bit suspect and, what's more, he already knows how to easily connect with the guards, as seen when he was stopped by a Russian guard in the Starcourt Mall laboratory and able to joke around. It's possible Murray became fluent in Russian and has intimate knowledge of life as a Russian guard from being one of their prisoners.
One final possibility which seems to be the most logical is Dr. Brenner (Matthew Modine). Brenner has knowledge of the Upside Down and an interest in using Eleven to spy on the Russians (as seen in season 1). Eleven supposedly killed Brenner at the end of season 1, but it was later confirmed by producer Shawn Levy that Brenner is still alive. For now, this option, as well as options known and unknown, will all have to stay on the table until we get more definitive clues about the American's identity, presumably when Stranger Things season 4 releases.