Kyou Kara Ma no Tsuku Jiyuugyou is the novel the anime and manga are based on. It's about a boy named Yuuri, who gets himself flushed down a toilet into another world. There, he finds out he's the Maoh (demon king) and that the Mazoku (demons) expect him to lead them against the human race.<br>
The novel is told from Yuuri's PoV, with plenty of side-commentary that is left out of the show.


Yuri Shibuya just can't catch a break. First, he had his head dunked in a toilet. Then he was transported to another world - where he finds himself king of the Mazoku's, a new race that expects him to lead them to war against all of humanity. And to top it all off, he's engaged - to a man!
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(Source: Viz Media)

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