He might be really angry at first. Naruto has always fought for recognition, and having the heir name taken away would feel like a huge slap in the face. So he could lash out, trying to prove his worth.
One possible reason could be political intrigue within the village. Maybe there are factions that don't want Naruto to have the heir name because they fear his growing influence. Another reason might be related to some hidden secrets about his family that are being unearthed, causing the village elders to question his suitability for the heir name.
One possible reason could be a plot by an enemy to undermine Naruto's legacy. By taking the heir name, they can create confusion and disrupt the line of succession in Konoha. It might also be part of a political maneuver within the village, where some faction wants to gain control over Naruto's influence through his heir's name.
It could be a rogue ninja who has a grudge against Naruto. This ninja might think that by taking the heir name, they can get revenge on Naruto in a very personal way. For example, if the heir name holds a certain significance in the village, using it wrongly can cause chaos.
At first, Naruto would likely be very confused and scared. Growing up without his parents' love and guidance, he might be more withdrawn or angry. He may have trust issues, as he was taken from the people who were supposed to protect him. This could make it harder for him to form close relationships later on.
Well, it could be that Naruto gets some kind of elemental powers from the comet. Maybe the comet is associated with a new, rare element that Naruto can then manipulate. This new power could give him an edge in battles, as his opponents would be unfamiliar with it. He could use it in creative ways, like combining it with his existing jutsu to create even more powerful attacks.
Well, if Naruto were to obtain a bloodline from Kami in a fanfic, it would be a huge game - changer. His physical and mental capabilities could skyrocket. He could have new jutsu that are on a whole different level, perhaps being able to heal at an accelerated rate or even have some sort of spiritual connection that allows him to foresee events. It would also likely cause a stir among the other ninja, who would either be in awe or fear of his newfound powers.
One possible plot twist could be that Naruto's parents were actually alive all along and in hiding. Danzo took Naruto to use him as a bargaining chip against them later. Another could be that Danzo believed Naruto had some special power within him from birth that he wanted to control for the village's 'greater good'. Maybe Naruto's parents knew about this impending threat from Danzo and had a secret plan in place for Naruto to overcome it.
In such a fanfiction scenario, first of all, the Volturi would likely have their reasons for taking Renesmee, perhaps believing she is a threat to the vampire world order. Once taken, the Cullens would be desperate. Alice might use her visions to try to find Renesmee's location. Jacob could also play a crucial role as he has a special bond with Renesmee. He may attempt to lead a rescue mission or at least try to communicate with her while she is in the Volturi's custody. The story would be filled with drama, action, and the exploration of relationships between different characters in the 'Twilight' universe.
Naruto's perspective on the ninja world could change. With the Rinnegan, he would see things in a different light, both literally and metaphorically. He might have to deal with new enemies who are attracted to his new power or new responsibilities that come with such a powerful dojutsu. His relationships with his friends and allies could also be affected as they may view him differently now that he has this extremely powerful ability.