A great plot might involve a character who has the Fourth Dojutsu but has to keep it a secret from everyone. As they struggle with this burden, they start to realize that there are dark forces that are aware of their power and are trying to manipulate them. This creates a lot of internal and external conflict for the character.
It could be a descendant of an unknown clan. This character might have been living in obscurity until they discover their latent Fourth Dojutsu abilities. They then enter the world of shinobi and start making a name for themselves.
Well, one way could be through some super - rare and powerful jutsu that transfers the dojutsu abilities to him. Maybe a forbidden jutsu that was long forgotten but he stumbles upon it somehow.
In some fanfictions, Naruto might obtain all dojutsu through some kind of ancient inheritance. Maybe he discovers a long - lost scroll or a hidden temple that bestows upon him these powerful eye techniques.
He could get a Dojutsu that allows him to manipulate time. This would be a very powerful ability as he could slow down or speed up time during battles. For instance, he could slow down time to dodge an enemy's attack and then speed it up to counterattack.
Well, it could make him an even more powerful ninja. The Dojutsu might give him new abilities like enhanced perception, the ability to see chakra more clearly, or even some kind of special attack. For example, if it's a Dojutsu similar to the Sharingan, he could potentially copy jutsu more easily.
Well, in some fanfictions, he might obtain it through a strange encounter. Maybe he stumbles upon an ancient relic during a mission that contains the power of the broken eye dojutsu and it somehow bonds with him.
The balance in the ninja world would be completely disrupted. Allies might start to fear him as well. Naruto would have to be very careful about how he uses his powers to avoid causing chaos. He might also face moral dilemmas. For example, some of the dojutsu might give him abilities that could be considered unethical if misused, like mind - control - like powers. So he'd need to figure out the right way to use all these new powers.
He might gain enhanced perception. This could allow him to see chakra flow more clearly, similar to how the Sharingan can. So in battles, he can anticipate his opponents' moves better.