One way could be through a time - travel or dimension - crossing plot. Maybe a powerful jutsu goes wrong and opens a portal to a world where Jack the Ripper exists. Naruto's mother stumbles upon it and has to stop Jack from coming into the Naruto world. She could use her motherly instincts and ninja skills to fight him off.
Perhaps a group of rogue ninjas are trying to summon a powerful and malevolent force, and they accidentally summon Jack the Ripper into the Naruto world. Naruto's mother gets wind of this and steps in. She has to not only deal with Jack the Ripper's brutal and unpredictable nature but also the rogues who brought him here. She could use her strategic thinking and combat expertise to outmaneuver them all and send Jack back to where he came from.
I'm not very good at writing fanfics directly. But I can give some ideas. Maybe in this fanfic, Naruto's mother could be in a situation where she has to face the mystery and danger brought by Assassin Jack the Ripper. She could use her ninja skills to try and solve the mystery and stop him from harming others in the Naruto world.
First, do your research on both Naruto and Jack the Ripper. Know the abilities and personalities of the Naruto characters and the historical facts about Jack the Ripper. Then, come up with a unique premise, like how the two worlds collide. For example, if Naruto is on a mission in a world that resembles Victorian London. Next, create interesting characters interactions. Maybe Naruto befriends a detective who is trying to catch Jack the Ripper.
Well, one possible plot could be that Naruto somehow gets transported to the time and place where Jack the Ripper was active. He might use his ninja skills to try and stop Jack the Ripper from committing his crimes. Maybe he'd start by investigating the murders in his own unique way, using his shadow clones to gather information from different parts of the city at once.
It's very possible. The fanfiction community is known for its creativity and willingness to blend different concepts. Given Naruto's curious and adventurous nature in the original series, a writer could easily write a story where he becomes intrigued by the mystery surrounding Jack the Ripper and thus be a 'fan' in the context of the fanfiction, exploring how Naruto's worldviews might be affected by this interest.
Headphones can be integrated as a tool for communication during stealth missions. For instance, they could be modified to transmit and receive messages in a way that's undetectable by normal means in the Naruto world. This would be useful for teams of ninjas working together in enemy territory.
Another way is to make the bone claws a product of some sort of experiment. Orochimaru, for instance, is known for his experiments. He could create a test subject with bone claws, and this character could then escape and become a part of Naruto's world, causing all sorts of chaos and new storylines to develop.
The 'alaervez empire' can be integrated by having a historical connection. For instance, perhaps in the past, there were some ninja from the Naruto world who founded the alaervez empire. This would give a reason for the similarities in some aspects like the use of chakra - related abilities. Also, cultural exchange events can be used. If the alaervez empire has a different form of ninjutsu, they could hold a tournament or an exhibition where Naruto characters can participate and learn about it.
One way could be Naruto's ninjutsu skills being translated into unique combat arts. For example, his Shadow Clone Jutsu could be a special ability that creates temporary clones to distract enemies in battle, similar to how some Fire Emblem characters have skills to create decoys.
Naruto's ability to make friends easily could also play a big role. He could form alliances with students at U.A. High School. His positive attitude would be a contrast to the dark shadow of his 'villain' father. For example, he could befriend Midoriya and they could learn from each other's experiences of growing up different from the norm.
To integrate new characters well, give them a unique backstory that ties into the overall Naruto lore. For instance, a new character could be a survivor of a village that was destroyed by Orochimaru in his experiments. This character's quest for revenge against Orochimaru can bring them into contact with Naruto and his friends. Also, their special abilities should complement or contrast with the existing characters' powers in an interesting way.