The villain in the fanfic could also be considered a main character. If Naruto is using Shiki Fuujin, it's probably against a powerful enemy. This enemy's motives and power level would play a crucial role in the story and how Naruto decides to use the jutsu.
One interesting plot point could be how Naruto's use of Shiki Fuujin affects his relationships with his friends. Since it's such a powerful and dangerous jutsu, they might be worried about him using it.
In 'naruto uses shiki fujin fanfic', the story might focus on the consequences of Naruto using this powerful jutsu. It could explore how it affects his relationships with other characters. Since Shiki Fujin is a very dangerous and self - sacrificing jutsu, the fanfic could show how Naruto copes with the risks involved.
Well, one place to look could be on fanfiction.net. There are often a variety of Naruto - themed fanfics there, and you might be able to find some that involve Naruto using Shiki Fujin. Another option is Archive of Our Own (AO3). It has a large collection of fan - created works as well.
Well, in the fanfic, Naruto using crystal release could be part of a mission. Maybe he's in a land where crystal release is common among the enemies. He starts to study their techniques and somehow manages to adapt it to his own style. He could then use it to save his friends during a really tough fight. Like, he creates a huge crystal shield to protect everyone from a massive attack and then turns the shield into sharp projectiles to counter - attack.
In a fanfic where Naruto uses haki, it could change his relationships with other characters too. For example, if he shows this new power, some characters might be in awe of him, while others might be jealous. His training to master haki could also lead to new interactions with mentors or allies who are familiar with this power. Also, his use of haki could potentially attract the attention of new enemies who are interested in this unique ability.
In some fanfictions, Naruto Shiki might possess the power to manipulate shadow elements in extremely unique ways. For example, he could use his shadow to not only mimic the movements of others but also to create shadow constructs that can be used in combat, like shadow swords or shields.
A good 'naruto uses logic fanfic' often has Naruto making decisions based on rational thinking rather than pure emotion. This makes his actions more believable and his character growth more substantial.
Often, these fanfics explore Naruto's character development in relation to nintaijutsu. He has to learn new ways of thinking and fighting, which shows his adaptability. Also, the fanfics usually introduce new characters or groups that are related to the nintaijutsu aspect, like a secret clan that specializes in it.