She is a member of Kuro No Soshiki whose background is very mysterious. She was friends with Kudou Yukiko back when they were acting together under the name Sharon Vineyard. She has been secretly living at least two lives through the art of disguise: that of herself and her supposed daughter, 29-year-old Chris Vineyard. After staging Sharon Vineyard's death, she mysteriously rejuvenated and started living as Chris. Vermouth is the boss’s favorite which grants her some independence and has great personal interest in Edogawa Conan, constantly calling him "Silver Bullet". She knows about Ai and Kudo's reversion to their child forms, but keeps this knowledge secret from the rest of the Soshiki.