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)
Yumemi 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!!
She will often be seen with her assistant and fellow scientist, Kitashirakawa Chiyuri.
- Touhou Wiki: http://en.touhouwiki.net/wiki/Yumemi_Okazaki