Yukiko Kudō, originally Fujimine, is married to Yusaku Kudō and is Shinichi Kudō's mother. She left a successful acting career after marriage to prioritize her family. Her acting expertise provides her with advanced disguise and impersonation abilities, skills she uses for both playful pranks and investigative work with Yusaku. In the OVA "Aoyama Gōshō Tanpen-shū 2" segment "The Wandering Red Butterfly," Yukiko adopts the persona of "The Wandering Red Butterfly," a mysterious caller who sends Yusaku cryptic messages. This initiates a collaborative puzzle-solving adventure across the city, adapting an original Gosho Aoyama story with Yusaku and Yukiko replacing the manga characters. Throughout the franchise, Yukiko exhibits a mischievous and playful nature. She engineers intricate scenarios, such as faking Shinichi's kidnapping to evaluate his deduction skills and convince him to leave Japan for safety. Her theatrical flair includes utilizing disguises, even impersonating the Black Organization's Vermouth, to observe or subtly intervene in situations concerning Shinichi. Yukiko possesses sharp intelligence and keen observation, frequently partnering with Yusaku on cases. They sometimes offer indirect support to Shinichi during complex investigations. Knowledge of firearms, gained during her time in the United States, extends to training Shinichi in their handling. In non-canonical movie appearances, Yukiko contributes to developing a Sherlock Holmes-themed virtual reality game module, with the character Irene Adler visually based on her. A movie epilogue reveals a family connection: Yusaku discloses that he and Yukiko each have twin brothers, confirming Toichi Kuroba (the original Phantom Thief) as Yusaku's twin. Yukiko appears in 92 manga chapters, 55 anime episodes, 2 movies, 4 OVAs, and other media including openings, endings, and spin-offs like "Magic Kaito 1412."