One possible plotline could be that Sasuke sees Naruto with a powerful and unique sword. He becomes jealous because he feels Naruto is getting more attention or power because of it. So, he starts to train harder to prove he doesn't need a sword to be strong. Maybe he challenges Naruto to a sparring match to show that his own skills are superior without any fancy weapon.
Well, perhaps in the fanfic, Sasuke has always been the one with more traditional ninja weapons and skills. But when Naruto shows up with this amazing sword, Sasuke's jealousy kicks in. He might start to secretly investigate where Naruto got the sword from. He could end up finding out that there is a whole mystery behind the sword, like it has a special origin or a hidden power. And all this time, his jealousy is fueling his actions as he tries to either get the sword for himself or make Naruto lose it.
In the fanfic, Sasuke's jealousy of Naruto's sword could lead to some interesting character development. At first, Sasuke might be angry and bitter. But as the story progresses, he could realize that his jealousy is unfounded. Naruto might use the sword in a selfless way to protect the village or their friends. This could make Sasuke reflect on his own motives and goals. He might then start to see Naruto in a new light and instead of being jealous, he could learn from Naruto's example of using a weapon not for power or glory, but for the greater good.
Another plotline could involve a new character who befriends Sasuke. Naruto, being the competitive and close friend that he is, might get jealous of their budding friendship. This could lead to Naruto trying to insert himself into their activities and causing some comical or tense situations.
Maybe in this fanfic, Sasuke has gone too far in his quest for power and revenge. He starts attacking innocent people or trying to take over the Hidden Leaf Village. Naruto, as the hero, has no choice but to stop him. Naruto could use his talk - no - jutsu at first, but when that fails, he resorts to physical combat. He might start with his basic Rasengan and gradually level up his attacks as Sasuke counters with his Chidori and other powerful jutsus. In the end, Naruto destroys Sasuke's evil intentions and either kills him or imprisons him, depending on the tone of the fanfic.
In some fanfics, it could be a situation where they are trying to save the ninja world from a great disaster. They end up using a powerful jutsu that requires both of their life forces. They know that this jutsu will kill them, but they are willing to sacrifice themselves for the greater good. As they perform the jutsu, they share memories of their past, their rivalry, and their friendship, and then they die together, leaving behind a world that they have saved.
One possible plotline could be Ginny being jealous of Hermione's academic achievements. For example, Hermione always getting top grades and Ginny feeling inadequate in comparison, leading to some tense moments between them. Another could be Ginny's jealousy over Hermione's close friendship with Harry. Ginny might misinterpret their relationship and feel left out, which could create some drama.
One possible plotline could be that Naruto's mother, being an Uchiha, passes on some unique Uchiha abilities to Naruto. Maybe he has an easier time learning certain jutsus related to the Sharingan, even without actually having the Sharingan himself. For example, he could have a natural affinity for fire - style jutsus which are common among the Uchiha.
In this kind of fanfic, Ron's jealousy might also lead to some misunderstandings between him and Harry. Maybe he misinterprets Harry's actions as showing off his lordship. He could end up saying things he doesn't really mean in a fit of jealousy. It could also create tension within the group, as Hermione might be caught in the middle, trying to make both of them see reason.
One possible plotline could be that Sakura realizes her feelings for both Naruto and Sasuke are more than just friendship. She might become possessive out of fear of losing them. For example, she could try to keep them from going on dangerous missions alone. Another could be in a post - war scenario where she sees other people getting close to Naruto and Sasuke and her possessiveness kicks in as she has been through so much with them. She might start small, like being extra clingy, and then it could develop into more complex relationship dynamics as the story progresses.
One possible plotline could be exploring their shared heritage. Maybe they discover they are brothers early on and team up against the darker forces in the Naruto universe. They could use their combined powers to bring about a new era of peace in the shinobi world.
Well, it might be that Rias sees Naruto as a rival in terms of power or influence in a new setting. So, she uses her devilish powers to abuse Naruto. In the story, Naruto could start out confused and hurt but then draw on his ninja training and positive relationships back home to slowly turn the tables and make Rias see the error of her ways. Maybe he even teaches her about friendship and loyalty, which are concepts not as prominent in her world.
Maybe the story focuses on Naruto learning about leadership from Hashirama. Hashirama was the first Hokage and had great leadership skills. He could teach Naruto how to make tough decisions for the good of the village, how to inspire the people, and how to deal with political situations within and outside the village.