Sadao is the Demon King from Ente Isla who got way in over his head when the Hero Emilia showed up and started actively opposing him. Things went south fast, and he ended up retreating to present-day Japan—basically the human world—alongside Ashiya, one of his top generals. The catch? They both had to transform into human forms just to blend in and survive.
To make ends meet, Sadao ended up working the part-time grind at MgRonalds. He actually did well enough that he eventually scored a full-time position, which is kind of hilarious considering he's literally a demon trying to keep a low profile in a fast-food restaurant. Fans often note the absurdity of watching an interdimensional despot flip burgers for minimum wage, which is pretty much the whole appeal of his character.
Content compiled by AnimeList.moe from publicly available sources.
