Oyuki

Oyuki is a sulphurous high school student at the head of a biker gang with a rather unbridled sexuality. While Rumi and Ryô are on a date in a café, two members of his gang witness the transformation of the young man into a monster. They will then take pictures of his transformations and bring them to Oyuki. She immediately falls under Ryô's spell when she sees her photo, despite the warnings of her older sister Maki. She also discovers that Rumi attends the same school as her and begins to blackmail her by threatening her, so that she can introduce her to Ryô. Faced with Rumi's indifference, she decides to kidnap the couple with the help of her gang. In addition to being members of the same gang, she and her sister Maki both come from a wealthy family.