It's the eternal battle between good and evil, centered around Ente Isla. Emilia, the Champion of the humans is locked in mortal battle with the Devil King. As Emilia gains the upper hand, the Devil King opens a gate to another world, vowing to return and finish what he's started. As he and his second-in-command Alciel escape, Emilia has no choice but to pursue them, wherever that gate might lead.
And this is where we join our merry cast of characters in the manga The Devil is a Part-Timer (manga) Volume 1. To survive in this magic-bereft world, the Devil King (now called Sadao Maou) and Alciel (Shirou Ashiya) have to adapt to life on Earth. They get their paperwork in order, find a place to live within their nonexistent budget, and while Ashiya is researching magic in this world, Maou-sama gets a job to support them.
At MgRonalds. Taking orders behind the counter. Promoting their new Black Pepper Fries.
Eventually, the Champion Emilia Justina (now Emi Yusa) discovers where the Devil King has been hiding out, and confronts him. She's been marginally more successful at life on Earth, picking out a less strange name for herself, finding a decent apartment, and getting work at a call center. But even as she confronts Maou outside his work, there's something else going on as well. As they walk and bicker, his mighty steed Dullahan (a bicycle) receives a near mortal wound to its front tire. As they stop to inspect it, more gunfire erupts and they run for their lives.
Who else might know that they are more than they seem?
In the meantime, Maou-sama's coworker Chiho Sasaki has taken an interest in him as well. Ever since Maou appeared, she's been having strangely prophetic dreams about the earthquakes that have been plaguing the area, and she asks Maou out to talk about them. But with both Ashiya and Emi spying on them, things get awkward. And then another disaster.
The Devil is a Part Timer! (manga) Volume 1 does a good job keeping the action moving. Fans of the anime series might be annoyed that nearly four full episodes are contained in just the first manga. This shortening, however, keeps the pace quick and make sure the reader is never bored with overlong exposition. Fans who want a more in-depth look at the series may want to hold off and pick up the light novels when they come out later this year. However, for seasoned anime fans, as well as big fans of the anime, the manga is a fun reminder of the anime series and a good refresher before more of the plot is released for its English-speaking fans.
Highs: Emilia's backstory comes through better in manga form than it did in the anime, and really makes the reader start to cheer for the Champion
Lows: Pulled straight from the anime series, there's nothing new to offer storyline-wise
Verdict: The Devil is a Part-Timer! (manga) Volume 1 is a bit of a placeholder until further volumes come out for those who have watched the anime, but is still a hilarious romp for those for whom the story is new.
Further Reading: The Devil is a Part-Timer! Light Novel, Moribito, Rin-ne