Michael Walter Heyman, usually simply called Michael and nicknamed Squirt by his fellow ODSTs, was a member of the UNSC Marine Corps and later the Orbital Drop Shock Troopers (ODSTs), attached to the second echelon of UNSC SOCOM. He was known among his fellow ODSTs for his polite, enthusiastic, if somewhat dim-witted, nervous and clumsy behavior, fitting the bill of a stereotyped "green as grass" rookie. However, he was also recognized as a highly skilled soldier and a valuable part of the new-generation Alpha Company, 19th Shock Troops Battalion.