Otherwise known as the Demon Lord works at McDonalds. Yes, McDonalds was the only one evil enough to hire a demon lord.
Although really, they get around that in the series by calling it McRonalds. But we all know who they're talking about. So Hataraku Maou-sama is a light novel series that got adapted into a manga and then into an anime. It's about a demon lord who lost to the hero(ine) of light on his world and escaped to our world in a last ditch effort, bringing along his trusty servant; whatshisname. He soon discovers that travelling through dimensions has robbed him of much of his magic and cause him and his follower to turn into humans.
And because Japan apparently has some very very very lax citizenship laws, they're somehow allowed to stay in Japan, get an identity and rent a house there to live in while they try to find a way back. Unfortunately, this means they need money and without qualifications...well, they end up working in McRonalds. Hilarity ensues as Maou-sama tries to conquer the corporate world. Kinda...
Of course, the series wouldn't be complete without the heroine of light coming over to our world to try and finish off the Maou, only to find herself stuck in pretty much the same circumstances as him. More hilarity ensues.
Overall, the series is pretty light and decent, filled with a lot of fantastic one-liners such as Lucifers refusal to go back to heaven and declaration that 'heaven is being a NEET in Tokyo' among others. The people I've shown the series to all ended up liking it after the first episode, which isn't really something I can say for a lot of series. The only real issue I have with it is the fact it doesn't really explain a lot of things. Like how Maou-sama went from conquering demon to 'kindly' McDonalds manager in terms of personality but then again, this series was only 13 episodes long and didn't cover much of the original and ongoing LN series. If anything, this definitely deserves a 2nd season so that more can be explained. That or someone at Baka-tsuki needs to translate this now.