Kawaki makes his appearance in Boruto manga at a specific point, but I can't recall exactly. You might want to check the official manga sources for the precise chapter.
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.
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.
One interpretation could be a dark twist on Harry's character. Maybe in this fanfiction, he's been corrupted by some dark magic that makes him steal life force to gain power. It could also be a misinterpretation of some powerful spell he uses that seems to drain energy, which is wrongly seen as stealing life force.
There are far - reaching consequences. On a personal level, the man may feel violated and powerless. His family and friends may also be affected as they know the truth but see it being misrepresented. In a broader context, it can undermine the trust in institutions associated with the empire. If the empire is known for stealing stories, people will be less likely to believe any official narrative. It can also lead to social unrest as those who know the truth may fight against the false narrative imposed by the empire.
Often, empires seek to control the narrative for political or ideological reasons. If a man has a story that challenges the empire's status quo or power structure, they might steal it by distorting the facts, bribing those who could spread the true story, or simply ignoring the man's perspective and presenting a false one as the truth.
Kurama's death in the manga is final. There's no indication or plotline suggesting that Kurama comes back to life. The story moves forward without this happening.