He might show his scars to Sasuke. Given their complex relationship, it could be a powerful moment between them, a way to show Sasuke that Naruto has also faced great pain in their separation and the events that followed.
In the context of fanfiction, it might also be a plot device to explore Naruto's vulnerability. It could lead to new character developments, such as others seeing him in a new light. Maybe it causes some characters to re - evaluate their relationship with him, while for others it could be a source of inspiration, seeing that even someone as strong as Naruto has his own set of hardships.
One possible reason could be that he doesn't want others to pity him. Naruto has always been a proud and strong - willed character. His scars might be a reminder of painful past experiences, and he prefers to deal with them privately rather than showing vulnerability to others.
One possible significance could be a sign of his growth and the battles he has endured. His scars are like a visual record of his journey, showing how he has overcome difficulties. They might also be a way to connect with other characters on a deeper level, as they can see the physical toll his life has taken.
Some characters might be shocked and saddened. They may have known Naruto as a strong and energetic person, and seeing his scars would make them realize the hardships he has faced.
In the fanfiction, Naruto might use his chakra control skills to create a genjutsu that alters the perception of those who see him. He could project an image of his unscarred self over his actual body. For example, he focuses his chakra on the area around his scars and manipulates the light and the way it reflects off his skin in the eyes of others, making the scars seem to disappear.
On the other hand, his scars could strengthen his relationship with his mentors. Kakashi, for instance, might see the scars as a mark of Naruto's growth and maturity. He could take Naruto on more challenging missions, trusting that he has learned from whatever experience gave him those scars.
Perhaps Naruto is tired of the pitying looks he gets from people when they see his scars. By hiding them with genjutsu, he can avoid those uncomfortable moments and be treated as just Naruto, the powerful ninja, rather than Naruto, the one with the scars. Also, he may not want his enemies to see his scars and think they've managed to truly harm him, so he uses genjutsu to keep up a facade of being unscathed.
In this fanfiction, the 'death in his scars' could potentially symbolize the many near - death experiences Harry has had throughout his life. Each scar might represent a moment when death was close, and it could also be related to the idea that Voldemort's attempts on his life, which left the scars, are a form of death lingering within him. It could add a very dark and deep layer to Harry's character, showing how he has been marked both physically and psychologically by the threat of death.
One common way is through loyalty. He'll always stand by his brother no matter what. Another is by listening. He gives his brother his full attention when he has something to say.