She's Masumi's fiancee, beautiful, cultured and rich but she has a weak health. Masumi's father chose her for him since their marriage of convenience would be advantageous for both families. She's in love with Masumi but he doesn't love her back. Little by little she realizes Masumi's feelings for Maya and gets unstable. Her love for him is almost obsessive.
SpoilerAfter finding out Maumi's identity as Maya's purple rose fan, she tries to create 'incidents' where she put Maya in the situation where she is at fault. Ex. Bump into Maya who's holding juice and making it stain her dress and go all gaga about it and tattled to Masumi. Thus, when Masumi found out the truth that Shiori was plotting against Maya and trying to make him hate her, he broke their engagement. As of currently, she's recovering at her house from her crazy attempt in commit suicide because Masumi broke their engagement.
MAL
