A character from the yuri eroge series Sono Hanabira ni Kuchizuke wo. Paired with Oda Nanami. An extremely intelligent young lady who is the idol of the St. Michael's campus, as well as its student council president, she is also excessively doting and remarkably perverted in private.
Around others, she is quiet, thoughtful, and considerate, but around Nanami she is more self-centered and playful, and cannot (or will not) hold back her feelings. Her dual personality is illustrated in her first encounters with Nanami; the first time they meet, Yuuna mends Nanami's skirt when she rips it on her first day of class, but she's so taken with Nanami she manipulates the student council selection process to get her accepted so they can be together more, and the first yuri scene in the game occurs when Nanami walks in on Yuuna masturbating while sniffing her clothing and calling out her name.