渋谷 有利

Yuuri Shibuya (渋谷 有利 Shibuya Yūri) is the protagonist of the story. He was born in Boston, Massachusetts in the United States and grew up in Saitama, Japan. He is a high school student who enjoys baseball more than textbooks. The kanji Yuri's parents chose for his name Yūri means profitable, so people make fun of him by saying Shibuya Yūri, Harajuku Furi (roughly translated meaning "if Shibuya is profitable then Harajuku is unprofitable"). His mother insists that he is named Yuri because he was born in July and it has nothing to do with money or the fact that his father is a banker. In the English dub, this became the pun "Yuri is short for urine." He later finds out that Conrad inspired his mother to use the name since he mentioned while she was in labor that, where he comes from, July is called Yūri.

When Yuuri first arrives in The Demon Kingdom, he is told that he is the 27th King of the Demons. Throughout the series, he strives to create a world in which demons and humans can live together in peace, something that progresses slowly but surely as the series goes on.

Yuri easily gets caught up in his emotions, to the point he loses control of himself. He is quick to anger, and once he's angry he cannot stop himself. When he is angry or sad or feels a strong emotion his powers emerge. Yuri is a huge fan of Japanese historical dramas and so when he is in this mode he uses expressions from those dramas. Fans call this condition "Maou mode" (or emperor mode in Japanese). In the novel there is no note of his appearance changing, while in the manga and anime his eyes become slitted and his hair may grow longer.