In the fanfic, Naruto being cold after the Kage Summit could lead to some interesting character developments. His friends might be worried about him and this could strengthen their bonds. Also, it could be a sign of some sort of new power or curse that he got during the Summit, which would then drive the plot forward as they try to figure out what's wrong with him.
She could be confused at first. She might not understand why Naruto is suddenly ignoring her, since they were friends before. So she might try to approach him to ask what's wrong.
A new, young ninja from a minor village could be the main character. They could be trying to make a name for themselves and their village at the Kage Summit. They might get involved in some political intrigue or even a fight between the Kages and prove their worth.
One possible reason could be that something happened during the Kage Summit that made Naruto lose trust in Sakura. Maybe she made a decision or took an action that he didn't agree with. For example, if she sided with someone against Naruto's ideas regarding the situation at the Summit.
The fanfiction might explore Dark Naruto's motives during the Kage Summit. He could be on a mission to expose the secrets that the Kages have been hiding from the shinobi world. His actions at the summit could be a way of shaking up the established order. For example, he might reveal a conspiracy among the Kages that has been affecting the balance of power in the ninja villages. This would not only put the Kages in a difficult position but also force the other shinobi present to re - evaluate their loyalty.
It could be Naruto himself. Since he has a connection to all the villages in some way, he could play a crucial role in the fanfic, perhaps as a mediator or someone who uncovers a hidden conspiracy during the summit.
Perhaps in the fanfic, a young shinobi manages to infiltrate the Five Kage Summit and has a significant impact on the discussions. This shinobi could bring new ideas or warnings that change the course of the kages' decisions. For example, he might have uncovered a plot by a rogue ninja group to take advantage of the kages being gathered in one place. This would not only create tension between the kages and the external threat but also among the kages themselves as they debate how to handle this unexpected situation.
A plot could revolve around a mysterious threat that targets the Kages during the summit. It could be a long - forgotten enemy or a new dark force. The Kages have to put aside their differences and work together to face this threat. They might also discover some secrets about their own villages in the process of fighting this common enemy.
One interesting Kage Summit Naruto fanfiction could be one where Naruto has a secret plan during the summit that no one anticipates. He might use his charm and newfound diplomatic skills to sway the Kages in a direction that benefits the entire shinobi world.