Minakami Mario is one of the seven main protagonists in RAINBOW. The seventeen year old, nicknamed Mario has been detained to two years of confinement in the Shonan Special Disciplinary School. He was found guilty of inflicting grave injuries on one of his teachers who attempted an act of violence towards a female student.

Mario is strong willed and hates being looked down upon. He was the first one to start a fight in day one soon after being confined in a cell with Sakuragi.