His relationship with Iruka could be more intense. Iruka, who has also lost a lot during the war, might see Naruto as a chance to heal his own wounds. He could be even more nurturing towards Naruto from the start.
With Sasuke, Naruto's bond might form out of a shared understanding of loss. Sasuke has his own traumas from the Uchiha massacre, but Naruto, having grown up during the war, would have his own set of traumas too. They could bond over their pain and their determination to become stronger in different ways.
His relationship with the older shinobi like Kakashi would be different. Kakashi, being a veteran of the war, might see Naruto as a symbol of the future that they are fighting for. He could be more strict in training Naruto, but also more protective, knowing that Naruto represents the hope for a post - war world.
Naruto's Rasengan would be a game - changer. It's a powerful and unique jutsu that could easily take out many opponents during the Third Shinobi War. His ability to use the Nine - Tails' chakra would also make him extremely formidable. He could enter the Nine - Tails' mode and overpower a large number of enemy ninjas at once.
The relationship with the village elders would be complex. They might have seen him as both a great hope and a potential liability. His relationship with the other Jinchuriki could also be different. If he was known earlier as a Jinchuriki, he might have been in contact with others, like Gaara, earlier. And his relationship with Sasuke would have an added layer. Maybe Sasuke's family would have seen Naruto in a different light, knowing he was born before the war and had some sort of special significance.
One implication could be that Naruto grows up in a more war - torn environment. He might see more death and destruction from an early age, which could make him more determined to end wars. For example, he might witness the pain of orphans like himself on a much larger scale, fueling his desire for peace.
In a fanfiction where Naruto is born during the Second Shinobi War, he could potentially be a major asset to the Leaf Village much earlier. Since he's the jinchuriki of the Nine - Tails, his power could be harnessed for the war effort. However, this also means he'd be in more danger from enemy villages who would want to either capture or kill him. His relationship with the villagers might be different too. Instead of being shunned for the Nine - Tails inside him, they might see him as a necessary evil for the village's survival.
His relationship with Sasuke would be greatly affected. Sasuke, who has always been somewhat defined by his rivalry with Naruto as a shinobi, might not know how to interact with Naruto anymore. They could grow apart as Sasuke still pursues the shinobi path while Naruto abandons it.
Well, in a fanfiction where Naruto is born before the Third Shinobi War, it could mean that the prophecy about him might have been known earlier. This could have led to different training methods for him. Maybe the Sannin would have been more involved in his upbringing. Jiraiya could have started training him much earlier, and Tsunade might have been more focused on his physical well - being. Orochimaru, on the other hand, might have seen him as an earlier opportunity for power and tried to manipulate him much sooner. All these changes would have a huge impact on the overall Naruto storyline.
If Naruto was born before the Second Shinobi War, the story would be drastically different. For one, the political landscape of the ninja world at that time was very different. There were different power struggles and alliances. Naruto might have grown up in a more chaotic and war - torn environment. His presence could have potentially changed the outcome of some of the battles during the Second Shinobi War. Maybe he could have influenced some of the key players in a way that would lead to a different future for the ninja villages.
His relationship with Sasuke would likely be different. With Naruto being a sage from birth, Sasuke might see him as an even greater rival or, perhaps, someone to look up to more. Naruto could use his sage - like wisdom to better understand Sasuke's pain and motives, and might be more effective in bringing Sasuke back to the village earlier.
His powers would be seen as extraordinary. The Rasengan alone would be a very powerful and unheard - of jutsu at that time.
His relationship with Sasuke would likely be affected. Sasuke might be both intrigued and wary of Naruto's hollow abilities. They could have new reasons for rivalry, like Sasuke wanting to prove he's stronger despite Naruto's unique powers. Or, they could end up teaming up earlier to figure out what Naruto's hollow nature means.