It could also be a sparring session gone wrong. Naruto might be training with the Konoha 12, but his new and powerful techniques are too intense. This causes the others to feel threatened and they end up in a full - on fight. Naruto would then have to control his power and show his friends that he doesn't mean to harm them.
Perhaps there is an outside force influencing the Konoha 12 to fight Naruto. A powerful enemy could be using some kind of mind - control or illusion on them. Naruto would have to figure out how to break the spell on his friends while also fending off their attacks. He would be in a difficult position, as he doesn't want to hurt his comrades but also has to protect himself.
One possible plot is that there is a breach between the Naruto universe and the Hellsing universe. This causes chaos as demons from Hellsing start to invade Konoha. Naruto, being the hero, tries to figure out how to stop them. Alucard arrives, not entirely as an ally at first. But as they both realize the common threat, they join forces. Naruto learns about the different nature of the enemies from Alucard and adapts his ninja skills accordingly.
Perhaps the fanfiction could focus on Naruto's adjustment to the new environment in Konoha. He'd have to get used to the different training facilities, local customs among the ninja clans, and the overall layout of the village. For example, he might struggle at first to find his way around the various training grounds and meet - up spots for ninja teams. But as he explores, he discovers hidden gems in the village and forms closer bonds with the villagers.
Well, it could be about Naruto being wrongly accused and turning against Konoha. Maybe some false evidence is planted against him, making the villagers see him as a threat. So he decides to oppose Konoha to clear his name.
In a 'naruto conquers konoha fanfiction', perhaps Naruto could be pushed to the edge by the corrupt system in Konoha. He might decide to take over to bring real change. He could use his powerful jutsu and the loyalty of his friends to overthrow the old regime and install a more just rule.
In a dark 'naruto executed by konoha fanfiction', it could be that Konoha, fearing Naruto's power, decides to execute him. Maybe they believe false rumors spread about him. It's a very tragic and dark take on the Naruto universe.
In a 'naruto fights alone fanfiction', it could be that Naruto is on a mission in a foreign land where he has no support. The local ninjas are all against him for some reason. He has to use his Nine - Tails chakra in a more discreet way as he can't afford to go all - out and draw too much attention. He might befriend some local animals or spirits who help him in a more indirect way, like giving him information about the enemies' weaknesses.
Well, one possibility could be that Naruto uses his shadow clone jutsu to confuse the Humunculi. Since they are used to a more straightforward combat style, the clones might throw them off. Naruto could then use his Rasengan to directly attack them. Maybe he would also team up with some of the characters from the FMA world who oppose the Humunculi.
One possible plot could be that Zeref has a new target in the Naruto universe. Naruto discovers this and decides to confront him. At first, Naruto is outmatched as he doesn't understand Zeref's magic. But then he starts to analyze it during their battles and figures out ways to counter it. Meanwhile, Zeref is intrigued by Naruto's never - say - die attitude and chakra. The plot could also involve other characters from both universes getting involved, either to help or to cause more chaos.
Well, the plot could involve Naruto being in a post - apocalyptic world filled with zombies. His ninja skills would be put to the extreme test. He could team up with his friends like Sasuke and Sakura. Naruto would have to adapt his fighting style as zombies don't feel pain like normal foes. He might use his speed and agility to dodge the zombies and then use his powerful ninjutsu to take them out in groups.
Well, perhaps Naruto finds himself in a world where the Laguz are being oppressed. He decides to fight for them because he sees their struggle as similar to that of his own village. He could use his ninja skills to protect them from any threats, be it other powerful groups or some sort of dark force that wants to take advantage of the Laguz.