Shibuya Yuuri! I Am Maou

Wolfram takes Yuuri to an outlying village where Conrad and Gwendel are dealing with "a human threat". On their way there, they come across Adelbert, who attacks Yuuri. The quarrel is resolved; Adelbert escapes. Yuuri gets to see first hand the animosity between humans and Mazoku. When a little boy is injured trying to get a human criminal away from Yuuri, Yuuri finally realizes why he should become the official Maou of Shin Makoku. He aims to bring peace between the humans and Mazoku. His coronation involves putting his hand under a mini-waterfall. Contact with the water draws Yuuri back into his own world, back to Earth, and he finds out that no time has passed since he left.