One possible scenario in a Naruto - Kaneki fanfiction could be that Kaneki somehow ends up in the Naruto world. Maybe through a strange portal or some sort of jutsu gone wrong. He might initially struggle to adapt to the different environment and the presence of chakra. But his own unique kagune abilities could be seen as a strange new form of power in the Naruto universe.
Another idea is that Kaneki is brought to the Naruto world by Orochimaru. Orochimaru, being interested in Kaneki's unique physiology, wants to study him. Kaneki has to escape from Orochimaru's clutches and teams up with Naruto and his friends. Along the way, they discover that there are some dark secrets in the Naruto world that are related to Kaneki's past in a strange, unexpected way.
Well, you can try searching on fanfic platforms like Archive of Our Own. Look for tags related to 'kaneki x kaneki' and exclude any tags that might indicate lemon or adult content. There might be some great platonic or friendship - centered fanfics about these two characters.
A common theme is the exploration of their dual identities. Given that they are the same character in different states, fanfics might delve into how they interact with this shared yet distinct self - awareness. Another theme could be self - discovery, as they come to terms with who they are both individually and in relation to each other.
Unfortunately, Kaneki did die in the manga. This event was a turning point that brought about many changes in the storyline and the dynamics among the characters.
Well, the answer is yes. Kaneki's death was a significant event that had a big impact on the story's development. It was a heart-wrenching moment for many readers.