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 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.
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.
It could be the result of some kind of training or a new jutsu he developed. Maybe he learned from Gaara's unique sand - based defense and found a way to create something similar using his own chakra. For instance, he might have discovered a way to manipulate the natural elements around him in a similar fashion to how Gaara controls his sand.
Yes, there are likely many Naruto fanfictions where a character has the ultimate Sharingan. You can check popular fanfiction websites like FanFiction.net or Archive of Our Own. Just search for relevant keywords like 'Naruto', 'ultimate Sharingan' to find them.
One example could be Naruto developing a new jutsu that creates a chakra - based shield which is unbreakable. Another might be that he inherits a special power that gives him an automatic defense against all attacks. Maybe he forms a pact with a powerful spirit that surrounds him with an impenetrable barrier in the fanfiction.
One possible plot could be that Naruto discovers he has the ultimate Sharingan through some mysterious means. Maybe it was a hidden power passed down in his family that was dormant until a certain event triggered it. Then he has to learn to control this new power while still using his own unique ninja skills.
Well, if Naruto has a defense like Gaara, it would make him much more difficult to defeat. Gaara's defense is based on his sand, which can automatically protect him from attacks. For Naruto, this could mean that he could withstand more powerful jutsu from his opponents without getting seriously injured. This would give him an edge in battles as he could focus more on his offensive moves rather than constantly having to dodge attacks. Also, it might change the way his enemies strategize against him. Instead of trying to directly attack him, they might look for ways to bypass his new defense.
Yes, in some Naruto fanfictions, he can have an automatic defense. Writers often come up with creative ideas to enhance his abilities, and an automatic defense can be one such concept.