what happened to kawaki's arm

Well, it's a tragic event. Maybe she had to go through a lot of physical and emotional challenges to recover and adapt to her new life.

It could also be related to a prophecy or a pre - determined fate in the fanfic's plot. There might be some kind of dark prophecy that says Kawaki has to kill Naruto to prevent a greater evil. Or perhaps Kawaki is being controlled by an external force that has a vendetta against Naruto and uses Kawaki as a tool to carry out the murder.

I think he might have had a difficult time adjusting to life with the disability, but managed to overcome many challenges with courage and determination.

One common theme is friendship. Writers often explore how Himawari and Kawaki, who come from different backgrounds, form a bond of friendship. Another theme is growth. They both grow as characters, learning from each other.

No, Kawaki doesn't kill Naruto in the manga. The storyline doesn't go in that direction.

Yes, Kawaki has been introduced in the manga.

One common theme is growth. Both Himawari and Kawaki are often depicted as growing both as individuals and in their relationship. Another theme is acceptance. Since they come from different backgrounds, fanfictions usually show how they accept each other's differences.

One great 'kawaki naruto fanfic' could be one where Kawaki has to learn a new jutsu from Naruto. In many fanfics, Kawaki is often portrayed as a complex character trying to fit into the Hidden Leaf Village. He might struggle with his past and Naruto could be the one to guide him through it.

In such a fanfiction, perhaps Kawaki is driven by some extreme ideology. Maybe he believes Naruto's way of peace is a weakness and decides to take him out to change the ninja world in a more radical way.

In this kind of fanfiction, Naruto might teach Kawaki about the values of the Hidden Leaf Village. Maybe he'd show Kawaki how to control his powers better. For example, Naruto could take Kawaki on training sessions similar to the ones he had with Jiraiya.