You can start by thinking about the abilities and skills of the characters in your fanfiction. If your character is good at lightning - style jutsu, you could create a weapon that channels lightning, like a sword that can send out electrical shocks. Also, consider the cultural aspects of the Naruto world. A weapon that has a significant meaning in a certain clan's history could be a great addition to your story.
One way is to base the weapons on existing ninja tools in the Naruto universe. For example, you could create a modified version of the kunai, like a kunai with a hidden blade that can extend for surprise attacks. Another idea is to draw inspiration from nature. Maybe a weapon made from a special tree in the Hidden Leaf Village that has unique properties, such as being able to absorb chakra.
In this fanfiction, Naruto might also create a shield. This shield could be made from a combination of rare materials he discovers during his adventures. It has the ability to not only block physical attacks but also absorb and redirect chakra - based attacks back at the enemy.
He could become a weapons master through some kind of special power-up. For example, a new chakra form that gives him an affinity for weapons. He might be able to infuse his chakra into weapons, making them more powerful. And Naruto is known for his hard work, so he'd surely spend countless hours training with various weapons, from swords to shurikens, until he masters them.
Naruto could also make a staff. Given his connection to nature energy through Sage Mode, he could fashion a staff that can better conduct and store nature energy. It could be made from a special type of wood found in the Hidden Leaf's forest, which has natural chakra - absorbing properties.
Well, start with imagining unique functions and powers for the weapon. Then think about its design and appearance to make it stand out.
Some fanfictions describe that Naruto chakra weapons are created by skilled blacksmiths who have a basic understanding of chakra. They infuse chakra - conductive materials with the user's chakra during the forging process.
The katana would be really interesting. A katana in Naruto's hands could be a powerful weapon. He could use his speed and strength to make swift and deadly strikes. Also, a chained weapon like a kusarigama. He could swing it around with great force and use his ninja skills to control its movement in battles, entangling his enemies.
Let's say he gets a weapon that can transform. For example, it can change from a small dagger to a large spear. This would make his combat style more versatile. He could start a fight with the dagger form for quick, sneaky attacks, and then transform it into a spear when he needs more power and reach. This new weapon would force him to learn new fighting techniques and adapt his style to make the best use of its abilities.
[Book recommendation: Big Boss Is Cheated] This book was a novel about a gaming system. The main character, Lu Yin, obtained the right to be the heir of a certain god through rebirth. He had the ability to exchange skills, bloodlines, professions, props, and create characters in anime or games. The protagonist could play between reality and the other world in various animation dungeons, getting new experiences again and again. In addition, there were many types of weapons in the novel, including the profession of Weapon Master. Perhaps it could satisfy the interest of the emperor in creating Weapon Master mentioned in the question. I hope you like my recommendation. Muah!
Well, he might get a chakra - enhanced katana. It could be really cool as it can cut through almost anything with the added chakra power.
Start by coming up with a unique character concept for your OC. Think about their personality, abilities, and backstory. Then, integrate them smoothly into the Naruto universe, respecting the existing lore and characters.