Nusumi has short spiky brown hair and black eyes. He wears a pair of glasses, a white dress shirt with a red bow tie, and jeans.
Nusumi had raped women but escaped a court conviction due to a lack of evidence, and is killed by Kira as punishment.
Nusumi is an employee of the coffee shop CAFEEL, which is located in the underground section of Shinjuku Station. At 3:00 PM on December 27, 2003, while wearing a hood to obscure his identity, Light holds Penber hostage outside the coffee shop. At 3:03 PM, when Nusumi can be seen sweeping the floors, Light tells Penber that Nusumi will die in two minutes, and at 3:05 PM, Nusumi dies of a heart attack. This act convinces Penber of Kira's identity, so Penber follows Kira's instructions, leading to the deaths of the twelve FBI agents.
While investigating the circumstances of Penber's death, Naomi Misora passes by the coffee shop where Nusumi worked. She notes that four people died near Shinjuku Station that day, indicating that she knew of Nusumi's death at CAFEEL.