Nagumo is a tall man with short black hair and large, dark eyes. He is mostly seen wearing a polo with a large trench coat as well as black pants (presumably slacks) and formal shoes. He carries a long briefcase around his back in which it contains his signature, large, Swiss Army knife-like weapon. Nagumo has many tattoos, most of which are obfuscated by his clothing. Some tattoos have mathematical inspirations, in particular referencing the Golden Ratio.