It's possible that the main characters include some reformed villains from the original Naruto series. In this new age fanfic, they could be trying to redeem themselves. Or perhaps it's a group of outcast ninjas who are trying to prove themselves in a world that has become more competitive and complex in this new age of the Naruto story.
Naruto's family members like Hinata and his children are often main characters. Hinata has been his wife, and in old age stories, she would be there supporting him. His children would be learning from him, and their growth and relationship with their aging father can be a major plot point in these fanfictions.
I don't know for sure since I haven't read this specific fanfic, but it could be characters like Gaara. Given his connection to sand, he would be a likely candidate if the fanfic focuses on iron sand.
Well, let's consider Naruto's Rasengan. In Dragon Age Inquisition, it could be seen as a very powerful and unique form of attack. It might be mistaken for some kind of extremely concentrated magic spell. The Dragon Age characters would have to figure out how to defend against it. Meanwhile, the magic in Dragon Age, such as the ability to create barriers, could be used to contain or slow down Naruto characters in combat. And characters like Hinata with her Byakugan could provide excellent scouting abilities, which could be valuable for the Inquisition's military operations.
Naruto's Rasengan could potentially be combined with a Heroic Age weapon or power. For instance, if a Heroic Age character has the ability to enhance weapons, they could enhance a kunai with the Rasengan's power. It would be a deadly combination.
The relationship with the Hokage would be altered too. If Naruto is Hanabi, he would be part of the Hyuga clan's dealings with the Hokage. Hanabi as Naruto would be in a position of great influence. The Hokage would expect her to act like Naruto, but she would bring her own Hyuga - influenced mindset to the role. This could cause both confusion and new opportunities for the village's leadership and decision - making processes.
One underrated character could be Iruka. In a fanfiction set in the Heroic Age, he could be shown as a young and ambitious ninja, not just a teacher. He might have had his own adventures and battles that shaped him into the person we see in the main Naruto story. Another is Shino. He has unique abilities with his bugs, and in the Heroic Age, he could be part of a special unit using his skills in a more strategic and crucial way.
If Naruto and Kushina were the same age, Naruto might develop more of an empathetic side earlier. Since Kushina was known for her strong will and compassion, being around her could make Naruto more in tune with his emotions. He might not be as reckless as he was in the original story because he'd have Kushina to balance him out.
If Naruto was the same age as Kakashi, the power dynamics would be very different. Naruto might be more skilled and mature from the start. He could have been part of the earlier battles against the Akatsuki. Also, his relationship with Sasuke might have a different flavor as they would be closer in age and experience. For example, they might be more like equals in their rivalry, rather than Naruto constantly chasing Sasuke's level of skill.