No legal streaming service in Mongolia (Netflix, Viki, Amazon Prime) offers Mongolian subtitles for this film. You have two options:
Below is an original article written based on that intersection: i+saw+the+devil+mongol+heleer
For viewers specifically looking for a Mongolian-language version, these are typically found through local Mongolian streaming services or fan-translated "fandub" communities rather than major international retailers like eBay or Apple. No legal streaming service in Mongolia (Netflix, Viki,