I'm not sure specifically as there could be many different versions of a Naruto fanfic with that title. It might involve Naruto developing some ultimate form of defense, perhaps a new jutsu or a special power-up that makes him invincible against certain attacks.
Since it's a fanfic, the plot of 'ultimate defense naruto fanfic' can vary greatly. It might start with Naruto realizing the need for an ultimate defense after facing a near - defeat in a battle. So he embarks on a quest to find the knowledge or power to create such a defense. Along the way, he could encounter various obstacles like powerful enemies who don't want him to gain this ability, or he might have to make sacrifices to achieve it. This ultimate defense could be something related to his chakra nature, like a new way to manipulate his chakra for protection. It could also have an impact on his relationships with other characters, such as his relationship with Hinata getting stronger as she supports him during his journey to obtain this ultimate defense.
Most likely Naruto would be one of the main characters since it's a Naruto fanfic. He is usually the central figure in any Naruto - related story.
Well, it could be a unique kekkei genkai that has been given an ultimate defensive quality in the fanfiction. For example, a power that allows the user to transform into an indestructible form, similar to how Gaara can use his sand as a shield but much more powerful. This form could be able to deflect all kinds of attacks, whether they are physical, ninjutsu - based, or genjutsu - based.
Maybe Sasuke. He is known for his powerful Sharingan and in the fanfiction, his Sharingan could have evolved to give him an ultimate defense. He could use it to see attacks coming from all directions and then use his chakra to create a shield that is both strong and flexible, adapting to different types of attacks. For example, if it's a fire - based ninjutsu, his shield could absorb the heat and turn it into his own energy.
Well, it could be about Gohan and Naruto teaming up to fight a common powerful enemy. Maybe an evil force from another dimension is threatening both their worlds, and they have to combine their unique powers and skills to save the day.
Well, it could be about a character achieving an ultimate life form through some unique training. Maybe they discover a new chakra mode that transforms them into an ultimate life form with incredible powers like super speed and strength.
Another possibility is that some sort of cosmic event makes them both super - charged, Naruto becoming godlike and Spider - Man reaching an ultimate form. They are then chosen to stop an interdimensional threat that could destroy both their worlds. They would have to learn to trust each other quickly and use their combined powers to save the day.
One idea could be a story where the Sharingan evolves to an ultimate form that gives Naruto unique powers. For example, he might be able to use it to instantly teleport to any location he has previously visited. This would add a new dimension to his fighting abilities and his ability to save his friends quickly.
I'm not sure about the specific plot of this fanfiction as there could be many different interpretations. It might involve Naruto characters in a world where vampires exist, perhaps with Naruto having some new powers related to vampirism or facing off against vampire enemies.
It could be about a fan - created story where the main character has an ultimate form of love in the Naruto universe. Maybe it's a story of a character who has an all - consuming love for Naruto himself, or perhaps it's about a unique love story set within the Naruto world's framework of ninjas, battles, and friendships.
Since it's a fanfic, it could cover a wide range of topics. It might explore an alternate universe where Naruto was raised differently, which in turn affects his development as a shinobi. It could also focus on his training and how he masters skills that were only hinted at in the original series. The 'ultimate shinobi' part might imply that he reaches a level of strength and wisdom far beyond what we saw in the Naruto anime and manga. It could also delve into the political aspects of the shinobi world more deeply, with Naruto being at the center of some major changes as the ultimate shinobi.