Hoshikawa Subaru is the main protagonist of the series. After performing a Denpa-Henkan with War-Rock, he is referred to by the name Rockman.
A genial but a bit lonely fifth-grade student, Subaru mourns the disappearance of his father that occurred three years prior, and has neglected school as a result. After being confronted by his classmates who pester him to return to school, he heads to an observing platform where he discovers the fugitive FM-life form (in fact a survivor of the AM Planet’s destruction) War-Rock by donning the Visualizer glasses left to him by his father, which allow him to view the EM Wave World. War-Rock, having stolen the mysterious Andromeda Key from the FM King, claims to have knowledge of the boy’s missing parent. The two are able to merge together, and Subaru uses this new found power to protect his friends and others from the invading FM-life forms. At first War-Rock is put off by this because the feelings Subaru feels are foreign to him. War-Rock has a personal agenda of protecting the Andromeda Key, but as that runs side by side with protecting the Earth, he slowly begins to care for the planet as well as care about Subaru.