Kogane Musashi (武蔵 小金 Musashi Kogane?) is a former pupil at Furinkan High School who passed away but eventually returned to reclaim her lost treasure, an old tanuki doll which she lost and was unable to find before her death.
Kogane has long dark brown hair which reaches down to her waist. During her first appearance she wore her old Furinkan High uniform, before changing into a Yukata upon her return. Given her status as a ghost, Kogane has the ability to change her physical tangibility so that she can chose whether or not to interact with other objects as well as making herself completely invisible.
Unable to reclaim the doll before her death, Kogane's spirit returned after Akane read a song which had faded into the pages of her old notebook. Kogane then refused to leave until her "treasure" was returned to her. After following the clues mentioned in the song which brought Kogane back, Ranma and Akane find themselves back at Toramasa's store who finally returns Kogane's doll to her.
Kogane later returned during Tanabata where she met Hikaru Gosunkugi and the pair instantly bonded over their love of the occult. Unfortunately, despite the efforts Ranma, Gosunkugi and Akane, Kogane had to return to the afterlife by midnight, leaving Gosunkugi heartbroken.