It could cause some of his friends to be worried about him. They might be afraid that the power of the demon knife will change Naruto for the worse. For example, Sasuke might be especially suspicious, which could strain their relationship further.
Well, he could become a much more powerful ninja. The demon knife might have special abilities like being able to cut through any defense or it could give Naruto the power to sense his enemies from afar. He would need to learn how to control the power of the demon knife though, as it might be too much for him at first.
The sword might have special abilities that Naruto can tap into. For instance, it could allow him to use a new type of chakra or jutsu. Maybe it gives him the ability to control shadows or fire in a way he couldn't before. This would completely change his fighting style and make him even more formidable against his enemies.
There's also 'Butterfly Knife Bond in Naruto'. In this fanfic, Sasuke is the one who gets involved with a butterfly knife. He uses it in a very unique fighting style that blends his traditional ninja skills with the quick and flashy moves possible with the knife. It gives a fresh perspective on his character and his battles.
One possible scenario in this fanfiction could be that Naruto's sister constantly interferes in his ninja training. She might think the training is too dangerous for him and tries to stop him from taking on challenging missions. For example, when Naruto is about to go on a mission to the Land of Waves, his sister could try to convince the Hokage not to send him, believing that he's not ready yet. This would add a whole new layer of conflict to the story, not just between Naruto and his sister, but also with the village's expectations of Naruto as a ninja.
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.