Nagisa is a calm, collected and friendly individual who can be exceptionally observant and circumspect of his surroundings and the situations that develop around him. He tends to pay strict attention to Korosensei in hopes to understand the motives of the mysterious being and compiles the information he has gathered in his notes for reference. Nagisa is noticeably more reserved and shy than other students in his class, thinking much more than actually talking and referring to himself as "invisible" because of this. He seems to be commonly nervous about what he says in important situations, being hesitant and harboring a slight stutter, which is possibly due to his mother telling him he "isn't good enough". However, Nagisa is not easily fazed by things that would unnerve the average person as shown in his interactions with Karma Akabane and the prospect of using a real knife. Despite his calm and empathetic demeanor, Nagisa possessed deep insecurity about his talents and how he was perceived by the people around him. This was reflected by a lack of goals and general pessimism about his own future, which caused him to end up in Class 3-E. However, Nagisa eventually gained more self-esteem, became more objective, and found his own goals, thanks to his experiences with his classmates and especially with Korosensei.