Iruka would be inconsolable. He was like a father figure to Naruto in the early days. His death on his birthday would bring back all the memories of Naruto's growth and how far he had come. The village as a whole would go into mourning. Naruto was the hero who saved them multiple times. There would be a sense of hopelessness among the villagers, and they would struggle to find a new source of inspiration without Naruto around.
Naruto would probably be really hurt at first. He's always been someone who values his friends and to be forgotten on his birthday would sting. He might try to hide his disappointment though, putting on a brave face.
Sasuke would be deeply affected. He and Naruto had a complex relationship, from being rivals to friends. He would likely feel a sense of guilt, as if he should have been there to protect Naruto. Sakura would be heartbroken. She had always cared for Naruto, and seeing him die in such a tragic way in front of his parents would make her feel helpless. His parents, on the other hand, would be in utter despair. His father might feel like he failed as a father again, not being able to protect his son this time either.
If Naruto was an Ajin in a fanfiction, the characters in Naruto would have a mix of reactions. Hinata would be concerned for Naruto's well - being. She might be a bit scared at first because of his new and strange abilities, but still stand by him. The villagers, who have had a rocky relationship with Naruto in the past, might be afraid of him all over again. They could see his Ajin powers as a threat. On the other hand, Naruto's close friends like Shikamaru would try to understand what's going on and help Naruto control his powers if they can.
Sakura might be the first to notice. She would approach Naruto gently and try to get him to talk about what's wrong. She'd offer him some home - made cake and sit with him, sharing stories of their past adventures to cheer him up.
She would be heartbroken. Sakura has known Naruto for a long time, and his death would shatter her world. She may become more withdrawn and serious. In the long run, she could use her pain as motivation to become stronger. Maybe she would train harder than ever before to make sure that no one else has to suffer the way Naruto did. She might also start to see Naruto in a different light, realizing all the things she took for granted when he was alive.
Most of Naruto's friends would be outraged. Shikamaru, known for his intelligence, would likely come up with a plan to get Naruto out of this situation. Hinata would be very worried about Naruto and might even try to stand up to Kiba herself, despite her usually shy nature. The senseis in the village, like Iruka, would also not tolerate such behavior and would step in to put an end to it.
Sakura would be extremely worried. She would probably try to gather the other members of Team 7, like Sasuke and Kakashi, to go after them. Sasuke might be a bit more hesitant at first, but his loyalty to Naruto would eventually make him join the search. Kakashi, on the other hand, would be more strategic. He would try to figure out Minato's motives first and then plan the rescue mission accordingly.
The characters in 'Naruto' would be deeply affected if Naruto dies at birth in fanfiction. Jiraiya would be one of the most affected. He saw Naruto as his protege and the hope for the future. Without Naruto, Jiraiya might lose his enthusiasm for training and spreading his teachings. Tsunade would also be saddened as she had a connection to Naruto through her relationship with Jiraiya and Minato. The Rookie 9, Naruto's friends, would have a completely different dynamic. They might not form as tight a group without Naruto's energetic and positive influence. And the Sannin, as a whole, would have their relationships and legacies altered without Naruto in the picture.
Sakura might be a bit surprised at first, but then she would be happy for Naruto. She has always been his friend and would see that he is happy with Shikamaru. Kakashi would probably be very supportive. He has seen both Naruto and Shikamaru grow up and would understand their connection. Sasuke, on the other hand, might not show much emotion on the surface, but deep down he would be okay with it as long as Naruto is happy.
Sakura might be a bit surprised at first, but she would ultimately be happy for Naruto. She has grown past her initial crush on him and would see that Pakura makes him happy. Kakashi would probably be very supportive, seeing it as another step in Naruto's growth and a positive development for the ninja world. Sasuke might be more reserved in his reaction, but deep down he would understand Naruto's choice and respect it.