Mishima has disheveled, gray hair and light brown eyes hidden behind his circular yellow spectacles. He wears a brown suit with a lime-colored undershirt worn with a tie, alternating between green and orange stripes and brown dress shoes.

Being good-natured, if a little odd, Mishima often chuckles after sentences in a distinctive, suspicious manner. His genuine sentiments are often in contrast to his appearance. Mishima seems to enjoy acting strangely to amuse others, sometimes behaving in cryptic ways. He can be overly analytical of everyone's actions. His unusual social quirks aside, Mishima makes it clear he has no ill intentions and frequently reminds others to be safe and cautious. Mishima is an incredibly kind, caring, and encouraging person.

(He is one of the Death Game participants.)