A bit about Misao Minakami:

Misao, Tomoharu\'s childhood friend, is the female heroine of the series. In order to save Tomoharu\'s life, she became the Burial Doll of the Asura Machina Kurogane when they were involved in a plane crash three years before. Ever since then, she has been only visible to a handful of people as a Projection Body(known informally as a spirit). After Kurogane consumed the stabilizer plugin, she became visible to everyone and became a transfer student in Tomoharu\'s class...