Okazaki Yumemi (岡崎夢美) is the canonical final boss of the third Touhou game 東方夢時空 〜 The Phantasmagoria of Dim.Dream ("canonical" because it's a dueling shooter, so everyone fights everyone anyway).
An eighteen-year-old university probability physics professor from the future who got shunned by society for believing in magic, she comes to Gensokyo to capture its specimens and prove her theory is right. A genius even by the future's high standards, she's the creator of the Probability Space Hypervessel - something not only capable of travel between time and space, but also of ripping through the Great Hakurei Barrier.
Yumemi's outfit and appearance is primarily red: her eyes, hair, vest, skirt, and her cape are all red. Even the bow on her white blouse is red. Commonly, she will be represented by a red cross motif in reference to her in-game attacks; or strawberries, in reference to her theme music, Strawberry Crisis!!
Because of her occupation in what may be the outside world, she and her assistant and fellow scientist, Chiyuri are sometimes depicted knowing characters who are native to the outside world like Sanae or the SecretSealingClub.
