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.
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.
Iruka would be super affectionate. He'd probably be the one making sure everything is going smoothly and that Naruto is having a great time. Sasuke might be a bit aloof at first but would warm up and give Naruto a small but meaningful gift, like a hand - drawn picture of them as future ninja comrades.
Naruto characters 'birthdays were as follows:
1 Naruto Uzumaki: Born November 7, 1999.
2 Sasuke Uchiha: Born June 14, 1996.
3. Naruto Uzumaki's girlfriend: Born on March 18, 1998.
4. Orochimaru (Sasuke Uchiha): Born June 12, 1986.
Minato Boruto, born June 12, 1997.
6 Inuyasha: Born June 15, 1966.
7 White (Inara Uchiha): Born June 18, 1968.
8 Ichigo Amagasaki (Blackzaki Isshin): Born June 20, 1986.
9 Okami (Rem your figurine): Born June 28, 1984.
Naruto Uzumaki: Born June 10, 1997.
Oyai Touma: Born June 15, 1986.
12 I Love Luo (Sasuke Uchiha's father): Born June 18, 1968.
13 Scorpion (Mamami Mokura): Born June 7, 1989.
Dedale (Dedale): Born June 18, 1984.
Kano Kage: Born June 18, 1968.
16 Nara Uchiha: Born June 15, 1986.
17 Nagato (Chūzō Nagato): Born June 18, 1984.
Hyouka Chihiro: Born June 18, 1989.
19 Orochimaru's Teacher (Jūrō Dūjinn): Born June 15, 1968.
20 Flying Ape Asama (S Flying Ape Asama): Born on June 14, 1966.
Well, Naruto could initially be shocked that no one remembers. But then he might try to play it cool, because that's his nature. He could also think that they might be planning a surprise later. However, as time passes and still no one remembers, he would start to feel really down. He might even go off on his own to brood about it, wondering if he's not as important to his friends as he thought.
There's a chance it could be Shikamaru. Despite his laid - back attitude, he is quite perceptive. He might notice Naruto's subdued mood and put two and two together, realizing it's his birthday. Then he could rally the others to quickly put together a belated celebration for Naruto.
A 'Happy Birthday Sasuke' Naruto fanfic could be about Naruto planning a surprise birthday party for Sasuke. He might gather all their friends from the village, like Sakura, Kakashi, and Shikamaru. They could decorate Sasuke's old house with symbols of his clan, the Uchiha crest perhaps. Naruto would also make sure to have Sasuke's favorite food, tomatoes, available in abundance. It could be a story full of friendship and nostalgia, showing how much Naruto values Sasuke.
In some Naruto birthday fanfiction, there are often big parties. All his friends from Konoha, like Sasuke, Sakura, and Kakashi, gather to celebrate. They give him unique gifts. For example, Sasuke might give him a new jutsu scroll or Sakura could give him a handmade charm for good luck.
One idea could be a time - travel fanfiction where Naruto's friends go back in time to his birth and make sure his early years are filled with more love and support. They could prevent some of the early hardships he faced.