He is officially a handsome man. Even Pizza Nakajima, who attacked Sakamoto's shop, referred to Nagumo as 'handsome,' and during his time at JCC, he received 152 chocolates from female students on Valentine's Day, enough to carry them in boxes on a cart. Furthermore, when asked 'How would the characters live if they hadn't become killers?', author Yuto Suzuki replied that 'Nagumo would have lived as a model or actor in the entertainment industry,' confirming his status as an author-certified handsome man. His sharp visuals and physical build in every chapter further prove this. Compared to other characters drawn with sharp features, his eyes are notably rounder. His overall features look quite youthful, and many find his smiling expression cute, but the chilling gaze he shows when facing enemies or when extremely angry is so terrifying and eerie that one might wonder if he is the same person. He has many tattoos all over his body. The Fibonacci sequence on his neck, and mathematical symbols on both forearms, the backs of his hands, and his knuckles are the most prominent. In addition, foreign quotes, various geometric shapes, birds, and snakes are engraved. According to the fan book, some were done at a tattoo shop, while others he tattooed himself. He basically has a very sly and playful personality, which seems to apply to both allies and enemies alike. Because of this, during his first appearance, he disguised himself as Sakamoto to toy with Shin and Lu, lied about his age and personal details, and played a prank pretending to kill Shin with a toy knife at the Donden-kai massacre site, earning him a scolding three times. He also seems to get along—or perhaps clash—with the eccentric Osaragi. Though he seems inscrutable, he is surprisingly one of the most deep-seatedly affectionate characters in the work. His strong sense of camaraderie is often revealed, such as when he wears a lonely expression while mourning a fallen comrade, visits Sakamoto to warn him about a bounty, or tries to uncover the truth behind the death of Rion Akao, who was thought to have died long ago. As a killer who stood shoulder-to-shoulder with the legendary Taro Sakamoto, he possesses strength ranking 1st or 2nd even among the ORDER. During the Death Row Convict arc, X's faction assigned Nagumo an S-rank. He toyed with Minimalist—who kills people by compressing them with pure physical strength—using tricks and speed, and even surpassed him in strength, subduing him by the throat with one hand. His victory in a close battle against Gaku, an ORDER-level fighter from Slur's faction, and his combat scenes in flashbacks confirm he is an overwhelmingly powerful individual. Perhaps that is why Oki, the current leader of the ORDER, seriously considered Nagumo as the next leader. [His family is a family of spies.]