Kyo Kara Maoh!

Yuuri Shibuya is an average high school student whose passion in life is baseball. That is, until he intervenes in the bullying of a classmate, Ken Murata, and gets his head dunked in a toilet, and gets him flushed into another world. When he reaches dry land, he sees some people dressed in medieval costume and speaking in some weird vernacular. He assumes that it is a theme park of some sort. However, the people are afraid to see him and begin to pelt him with stones. There he met Adelbert von Grantz… Conrad Weller and Günter von Christ rescued Yuuri and took him to Blood Pledge Castle, the residence of the Maou, where he soon found out about himself. He meets some key characters, his fiance Wolfram for one, and soon finds himself being called the ‘Maou’, or Demon King. There, Yuuri learns he is to be crowned king and rules over ‘Shin Makoku’ (“Real Demonic Kingdom”) (眞魔国). Throughout the series, Yuuri is constantly confronted with the results of even the smallest choices he makes. With a strange power dwelling inside of him, Yuuri becomes a deliverer of justice in the world of Shin Makoku.