Nagito

Social disorders
Overall, Nagito seems somewhat disconnected from his own feelings. He tries to be polite, but can be overly harsh and insensitive, often without realizing it. He lacks social awareness and self-awareness. Because of this, he has trouble understanding how his own behavior can affect others, and he can be unable to pick up on social cues. He struggles with expressing himself in a socially acceptable manner, which often leads to people misunderstanding what he's trying to say, and vice versa. During the optional dialogue in Chapter 1, Nagito explains that he says questionable things without meaning, and he realizes this, but can't stop it. However, he also adds that he always speaks sincerely.

General behavior
Nagito has a relaxed and calm demeanor, often smiling and laughing. However, his cheerfulness may not be entirely genuine, as his calm resembles apathy, and he typically harbors intense self-loathing. He remains cheerful even during bouts of self-flagellation, and views terrible things like death with optimism, as long as he believes it's all for the sake of hope. When dissatisfied, he's very passive-aggressive. He's also skilled at manipulating people.

He compares his obsession with the Ultimates' hope to pure, platonic love for his classmates and sincerely believes he does everything for the good of others. Nagito desires to be useful, but his methods of helping are often deeply misguided, harmful, and potentially dangerous, as he seeks to induce temporary despair in order to extract hope from it. He cares little for his own well-being and doesn't care for his own life, urging others to kill him to achieve their own hope. He believes that dying for the sake of hope is an honor and the only way "someone like him" can be useful to the world. He likely suppresses any real feelings of sadness or fear as a coping mechanism, as he often experiences tragedies due to his good fortune. He has also seen very strange and unlikely things thanks to his good fortune, making him not easily surprised. As a result of everything he has experienced, Nagito has become more emotionally numb and rarely shows open anger or fear. He often lacks the appropriate emotion in situations that would cause most people to fear, such as threats of violence. Despite this, he once mentioned that he feels fear every day of his life, most likely due to Nagito's luck. Furthermore, he can be greatly angered by despair and other things he considers offensive to hope. When expressing anger, he becomes noticeably more serious.

Although he claims to be a pessimist, Nagito often appears unusually carefree. He lacks tact, and sometimes speaks awkwardly, strangely, and disturbingly, without realizing it. At times, he sounds more convincing—Nagito scolds Hajime when the latter is overly pessimistic or when he thinks Hinata is bullying Mikan Tsumiki. He is particularly irritated by Teruteru Hanamura's attitude toward girls and decides to keep an eye on him to ensure he doesn't stalk anyone. Nagito tries to be the team's conflict resolver and optimist, often telling the others to have hope and cooperate. However, he isn't taken very seriously. Hiyoko Saionji ridicules him, finding his dramatic talk about hope and friendship tiresome. Komaeda is generally quite submissive and selfless, even agreeing with Hiyoko and others' comments. He believes hope is an absolute good, and any action taken in the name of hope is righteous, even murder. Nagito feels no guilt for harming others in the name of hope, believing it will always triumph in the end and justify all means. Komaeda believes that there is a constant clash between two hopes, and that "strong hope" will consume "weak hope" (he calls this process "poetry in motion"). Untalented people, despair, and weak hope are simply stepping stones leading to the creation of hope.

Like
Nice things
Beautiful people
I don't like it
Noisy places
Ugly people
Other signs of his illness include his hair color, skin tone, and hoarse voice. In Island Mode, he mentions that he has low stamina, very sensitive skin, and that he doesn't like running.

Nagito is a tall, thin young man with tousled snow-white hair and gray-green eyes. His gray hair and pale skin are the result of his progressive illness.
Komaeda wears a long, dark green coat with a jagged hem. Red squares are depicted on the right shoulder, and a large number "55" in the same color can be seen on the back. Another red, unidentifiable symbol is depicted on his white tank top. Nagito wears black jeans with a long chain attached to them, along with a small skull-shaped keychain. His brown shoes with black soles have two zippers.