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 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.
The birthdays of the tutor, Reborn, were as follows:
1. Italian Giovannianni's birthday: February 24, 1984
2. Italian Rebbi's birthday: November 29, 1980
3. American DiNoo's birthday: February 18, 1988
4. Japanese Tsunosuna (Reo)'s birthday: June 14, 1996
Bella's Birthday: April 16, 1988
6 Japanese Yuri's birthday: April 23, 1992
7 American Dio's birthday: June 17, 1984
8. Japanese Rebbi's replacement, Ribéry's birthday: April 27, 1990
9. American Arnold's birthday: June 19, 1986
10 Japanese Tsunayoshi (Reo's father)'s birthday: November 18, 1945
The above are only the birthdays of some of the characters. The birthdays of more characters may need to refer to the plot of related novels or comics.
I can't provide a list of birthdays for all the characters because many characters play different roles in different works and their birthdays may vary. At the same time, I can't find all the anime works or provide a complete list of characters. If you have a specific anime character and its birthday information, you can search for the relevant anime works and character information yourself or refer to the relevant anime character birthday list.
One possible scenario in this fanfiction could be that Naruto's friends all got caught up in some mission on his birthday. He's waiting for them to return, but as the day goes on, he starts to feel that familiar loneliness. He then decides to go to the training ground alone and train, using the physical exertion to mask his disappointment.
As I'm not familiar with the 'birthday boys novel', it's difficult to say exactly who the main characters are. But it's likely that the main characters are the boys whose birthdays are being focused on. There could also be supporting characters like their parents, teachers, or other friends. These additional characters could play important roles in shaping the boys' experiences around their birthdays, whether it's through giving gifts, providing advice, or being part of the birthday celebrations.