Crown prince or "Taeja-Jeonha" of Korea. He is portrayed in the beginning as arrogant and insensitive. Pressured to marry early, he accepts the choice his father and the elders give him (Chae-Gyeong) after being rejected by his girlfriend Hyorin. Shin later shows that Chae-Gyeong is the only one that is really close to him. He also doesn't want to let her go.
He's a first year student in the advanced section. With grades at the top, good conduct, and part of the student council, many see him as a role model for reliability. He's a straight-forward person with no malice. Neiro is immediately attracted to him when she sees him sleeping in the grass one day, but falls in love with him due to the fact that he isn't afraid of her like most other people.
A tomboy, optimistic girl that goes to another world. There she finds out that she has a power of a rukia (the power of the dead). Disguised as a boy, she ends up being a slave of Kuya, but they become friends and later she develops feelings for him.
Shin is a third-year in middle school at the beginning of the story. His parents run a bakery and he will enroll in a boarding school after graduating middle school. He falls in love with Akane and they start going out later on.
He is the son of an Egyptian diplomat and a transfer student at William's school. He's a character from the Makai Ouji game, that makes a cameo appearance in the manga. (Source: Makai Ouji Wikia, edited)
Shin is Keiko's father who is a priest.