It could also be related to his identity as Peter Parker. If he's trying to keep his Spider - Man identity a secret from his friends, he can't fully share his experiences. This secrecy might create a barrier, making him feel like an outsider even among those he cares about. For example, if his friends are sharing personal stories and he has to hold back parts of his own life, he'll gradually feel left out.
He could start by being more open with his friends about his feelings. Just telling them that he sometimes feels left out might make them more aware and inclusive.
In some fanfictions, Naruto might feel left out because he has a unique background. He was an outcast in the village at first. Maybe the other characters in the fanfic are forming groups or having relationships that don't include him. For example, if there are new teams being formed and he's not part of them, it could make him feel left out.
Naruto could try to reach out to the other characters. He's a very determined person, so he could make an effort to join in on their activities or conversations. For example, if they're having a training session, he could ask if he can participate.
Maybe it's some kind of special jutsu or a curse that backfires in a way that numbs his pain receptors. For example, a powerful sealing technique might have been placed on him accidentally or on purpose that has this side - effect.
The sudden weakness and paralyzing pain in his left leg could be caused by many reasons. The most common one might be a stroke, such as a cerebral hemorrhage or a stroke. In this case, one side of the limb would show signs of weakness and paralysis, indicating that the bleeding or blockage had spread to a larger functional area. In addition, the imbalance of the blood ions, such as hypokalemias, and sports injuries may also lead to sudden limb weakness and paralysis. If this happens, it is recommended to perform a head CT or head MRI examination to determine the cause and choose the appropriate treatment method according to the specific situation.
In fanfiction, Naruto could feel sick due to overusing his chakra. He often pushes himself to the limit in battles and training, and this excessive chakra use might take a toll on his body, making him feel ill.
There were many possible reasons why his left leg felt weak but he could walk normally. One possibility was muscle weakness caused by calcium deficiency, which was a common nutritional problem, especially in the middle-aged and elderly population. A lack of calcium could cause muscle weakness, cramps, and other symptoms. In addition, the lack of strength in the left leg could also be caused by abnormalities in the blood vessels, nerves, and muscles of the lower limbs. Common causes included poor blood circulation, damage or strain of lower limb muscles, abnormalities of lower limb nerves, and general diseases. To determine the specific cause, it is recommended that the hospital perform relevant examinations, such as lumbar spine frontal and lateral X-rays or lumbar spine CT, MRI, etc., to confirm the diagnosis and take corresponding treatment measures. In addition, appropriate calcium supplements and muscle exercises were also important measures to prevent and improve symptoms.
It might also be about how Naruto is treated or perceived in the fanfiction. If the other characters see him as a monster, either out of fear of his power or because of some misinformation or plot device, then that would create the feeling. This could lead to interesting storylines where Naruto has to deal with being ostracized or hunted because of this false perception of him being a monster.
The plot could involve Minato being brought back to life or having a vision where he steps into Naruto's shoes. He might feel Naruto's pain from constantly being underestimated because of his status as a Jinchuriki. This could lead to Minato trying to find ways to comfort Naruto from afar, or even influencing the events around Naruto in a supernatural way.