Well, he could become even more powerful. He might be able to defeat his enemies more easily, like taking on Akatsuki members with less effort. The legendary weapon could also give him new abilities or enhance his existing ones, such as making his Rasengan even stronger.
Perhaps it's a unique staff. A staff could have different uses, like being a conduit for chakra. It could also have hidden compartments or be made from a rare material that gives Naruto an edge in battles. For example, it might be made from a metal that can absorb chakra attacks and then redirect them.
Well, it could be a sword with the power to cut through any jutsu. Maybe it has some special markings that only Naruto can understand. It might also be a staff that can control the elements in a unique way, giving Naruto an edge in battles.
It could be a sword that can cut through any substance, like the Susanoo easily. Just imagine Naruto swinging it and slicing through powerful jutsu defenses as if they were paper.
If the weapon is a chakra - enhancing tool, it will boost Naruto's existing jutsu. For example, his Rasengan could become more powerful, being able to break through stronger defenses.
A fanfiction about Naruto getting the Kusanagi could also involve a time - travel aspect. Naruto could be sent back in time and end up in the era when the Kusanagi was first created. There, he meets the original wielder and learns from them. He then brings the knowledge and the sword back to his own time, using it to defeat a great evil that was previously unbeatable.
In a Naruto fanfiction where he gets a massage, it could be a really interesting scenario. Maybe he's injured from a tough battle and the massage is part of his recovery. It could also be a way for him to relax after all the stress of being a ninja. This kind of fanfiction might explore his reaction to the gentle touch and care during the massage.
One idea could be that Naruto discovers the tanto in an ancient shinobi relic site. He initially doesn't know how to use it but with the help of Kakashi, he starts to learn. The tanto could have some special powers, like being able to cut through chakra - based defenses. This would add a new dimension to Naruto's fighting style.
No. Slavery is an immoral and unethical concept, and while it may be in a fictional fanfiction context, it still promotes a very negative idea. Naruto is a series that promotes friendship, hard work and positive values, and such a concept goes against the spirit of the original work.
Yes, there are likely some 'Naruto Gets Pregnant' fanfictions out there in the vast world of fan - created content. However, such concepts often deviate from the original source material in very extreme ways.