Hiyo Osora is the main protogonist. In the monster world she is known as the White Crow which is believe to be a myth until Hiyo showed her wings to the whole student body of St. Monster High School.
Hiyo is very short and childish looking for her age, with many people (such as L) mistaking her for an elementary schooler. She has long blond hair that she usually keeps in pigtails, and blue eyes. When she brings out her wings at first, they are very small as her wings can only truly come out if she is in an emotional situation. At school she wears the standard uniform for girls. Outside of school (which is not often) she usually wears either a dress or a skirt.
Despite being a white crow monster, she is actually quite useless, often needing someone else to save her in times of trouble. The person that usually ends up saving her is Kurou. She secretly harbors feelings for him, but will repeatedly deny that she is his fiancé. Kurou asked Hiyo if he could just call her Hiyo, and she said yes.
Later on in the story Hiyo no longer denies her feelings. She adores food, video games, and everything cute. Ironically, she has a fear of heights; she developed the fear because she didn't know she had wings until she went to SM Academy.
When Hiyo was still young, a powerful witch erased all her childhood memories, and that is why she doesn't know how to fly until she attends SM Academy. Hiyo also forgot that she was the one who proposed to Kurou although she doesn't remember it due to the witch erasing her memory. Because of her childish and sweet behavior, Hiyo has many people who adore her and love her, but the only person she truly loves is Kurou.
Kurou Tenma- Kurou is Hiyo's fiancee and later, husband. He is very protective of her, usually beating anyone who hurts her to near death, or making the entire school search for her if she is missing. At first, Hiyo is very distrustful of him usually keeping her distance. However, as time goes on Hiyo starts to reoprecitate his feelings. It is revealed that Kurou is the Demon King, the lover of the white crow who went insane after his lover was kidnapped. Despite the story requiring Hiyo to kill Kurou, she goes against this and instead wishes for them to live in happiness.
L Bradford- At first, L and Hiyo hated each other. Hiyo for L calling Hiyo short, and L because Hiyo insulting him. In chapter 50 L and Hiyo become trapped in a cave looking for Kiki, a bat that Hiyo liked when L attempted to bribe her into giving her a feather. L showes remorse after his bites Hiyo and nearly changes her into a vampire. Hiyo forgives him and they become friends. When Hiyo finds out that L is in trouble, she immediately goes to see him, despite Kurou's objections (due to his jealousy.). Even though Hiyo rejects his affections, the two remain close friends.