Riou Mason Busujima, aliased as Crazy M, Riocchi, and Riorio, is a 28-year-old man of mixed American and Japanese heritage. Born on June 21st, he possesses a towering height of 191 cm and a weight of 74 kg, with light brown hair and multicolored eyes.

His background as a naval officer instilled a strict adherence to hierarchy and rank, leading him to follow orders without question—accepting even a superior's declaration that white is black as truth. This military experience defines his combat approach, showing no mercy to enemies in dire situations. Outside conflict, he exhibits a calmer demeanor and enjoys helping others. His hobbies include cooking practical, organic foods with professional skill, an ability that inexplicably unsettles teammates Samatoki Aohitsugi and Jyuto Iruma. He dislikes disorder, crowds, and processed foods.

As part of Yokohama's Mad Trigger Crew, he employs a hypnosis ability called "Shelter." His solo musical performance is titled "What's My Name?" His personal philosophy, captured in the statement "I submit to you that if a man hasn't discovered something that he will die for, he isn't fit to live," reflects his commitment to finding a purpose worthy of ultimate sacrifice, consistent with his military worldview.