Concrete Revolutio: Choujin Gensou: The Ones Who Look into Space

SINOPSIS

A young lady uses musical superpowers to slice and kill aliens lurking on Earth. Her name is Aki Haruka... A former singer for the Angel Stars known as Arachne. The Superhuman Bureau's investigation reveals her to be hiding out in a hospital that is illegally operated by Judas. Then Jiro escapes with Aki in order to protect her from those in pursuit. While on the run, Jiro starts telling Aki a story from two years ago about Rainbow Knight's helmet and a space being called a Fumer.