At first, Boruto would be in shock. But then, he would likely be filled with a new - found determination. He would vow to become as strong as Naruto, if not stronger. He'd study Naruto's techniques more intently and strive to protect the village in Naruto's place. Boruto would also carry the weight of Naruto's legacy on his shoulders, which would shape his actions and decisions in the fanfiction.
Boruto would be a mess of emotions. He'd feel guilt, grief, and a burning desire for revenge all at once. He might lash out at those around him in his pain. However, over time, he would start to channel those negative emotions into positive growth. He'd remember Naruto's teachings and use them to become a better ninja. His relationship with his friends and family would also change as he tries to come to terms with Naruto's death in this fanfiction scenario.
Boruto's reaction would be complex. He'd be heartbroken, for sure. He might start to question his own worth and purpose. But over time, he'd realize that he has to carry on Naruto's legacy. He'd become more serious and focused. He'd also become more empathetic towards others, understanding the weight of sacrifice. He might even start to study Naruto's techniques and leadership style more closely, trying to emulate the things that made Naruto such a great Hokage and hero.
Tsunade herself would be in a state of shock and deep remorse. She might blame herself for Naruto's death, thinking that she should have been stronger and not needed saving. The villagers would also be greatly affected. The children who looked up to Naruto as a hero would be heartbroken. They would start to tell stories about his bravery, and some might even be inspired to become like him, despite his tragic end.
She would be devastated. Hinata has deep feelings for Naruto. His death would likely cause her to go into a state of shock and disbelief at first. She might blame herself for not being strong enough to protect him.
Naruto might also try to remember Sakura in a positive way. He would cherish the memories they had together. He could start initiatives in the village in her name, like promoting medical ninja training more, since Sakura was a great medical ninja. He would slowly turn his grief into a force for good in the village.
One possible plot could be that Naruto sacrifices himself to protect Boruto from a powerful new enemy. Maybe an ancient evil has been awakened and Boruto is in its direct path. Naruto, being the hero he is, steps in and uses all his power to stop it. His death then becomes a catalyst for Boruto's growth, driving him to become stronger and more determined to protect the village in Naruto's memory.
He would be filled with rage. Naruto has a strong sense of justice and the fact that someone took Hinata away from him would fuel his anger. He would vow to find and punish whoever was responsible. He might even become reckless in his pursuit of vengeance, endangering himself and those around him. His friends would have to step in to try and bring him back to his senses.
Naruto would be devastated. Sasuke is his closest friend and rival. He would likely go into a state of deep mourning at first. He might isolate himself for a while, just trying to come to terms with the loss.
Some fans might like it. They could see it as a way to show Naruto's strict parenting side and how he is trying to instill good values in Boruto. It would add a new dimension to their relationship.
They could be shocked. Some might not expect the wild ideas that fans come up with in fanfiction.
Naruto would likely be excited. He loves his son so much that seeing different stories about Boruto would be like seeing different potential futures for him. He might even get some inspiration from the fanfiction to give Boruto some advice in real life.