Miko Yoshinaga is a shrine maiden serving at Hokkaido Toshogu Shrine. She possesses detailed knowledge about the swords connected to Toshizo Hijikata, the vice-commander of the Shinsengumi from the late Edo period. In the story, she appears after the arrest of Hijiri Fukushiro and seeks to speak with Detective Yoshihisa Kawazoe. Kawazoe directs her to Conan Edogawa and Heiji Hattori instead. She then reveals that the box sought by multiple parties contains a sword known as the Seiryoto, which features a star-shaped tsuba. She further explains that the Seiryoto was stolen from the shrine several years earlier and mentions that Goryokaku had once been set on fire. Her information proves crucial to understanding the true nature of the treasure and the mystery surrounding the swords. Miko Yoshinaga’s motivations are grounded in her desire to provide accurate historical context and assist in resolving the case. She interacts primarily with Conan and Heiji, to whom she entrusts the knowledge she holds. Her development is limited to this pivotal exposition scene, but her calm and informed demeanor establishes her as a reliable source of key background facts. Her notable ability is her extensive familiarity with the shrine’s artifacts and the history of the Hijikata-related swords, which she uses to clarify the path toward the hidden treasure.