Kakashi's character would likely become more confident in his abilities. With the Dual Mangekyou Sharingan, he has access to greater power, which could boost his self - assurance. He might take on more dangerous missions without hesitation.
His sense of responsibility would grow. Knowing the power he holds, he would feel an even greater obligation to protect his village and his comrades. He would be more involved in strategic planning and decision - making for the safety of all. Also, he may have to deal with the envy or fear of others in the village due to his new power. This could make him more isolated at times, but also force him to communicate better and prove his intentions are good. He might start to mentor younger ninjas more intensively, passing on his knowledge about the Sharingan and how to handle great power responsibly.
Perhaps a storyline where Kakashi's dual Mangekyou Sharingan makes him a target. Enemies from other villages might see his new power as a threat and try to either steal his eyes or kill him. This could lead to a series of intense battles and chase scenes. Kakashi would then have to rely on his wits and the help of his friends and comrades to stay alive. In the process, he could form new alliances and strengthen old ones, all while protecting his newfound power.
Naruto's character would likely become more complex. He'd have to deal with new powers and the responsibilities that come with them. He might become more introspective as he tries to understand the nature of the Sharingan and how it fits into his ninja beliefs.
The fanfiction might show Kakashi growing in terms of his understanding of the Sharingan's true nature. As he delves deeper into the abilities of the eternal Mangekyou Sharingan, he could gain a broader perspective on the Uchiha and their powers, which in turn enriches his own character development. He may start to see things from an Uchiha - like point of view, which was previously foreign to him. Also, the new power might attract new enemies or allies, and through these interactions, Kakashi will have to adapt and grow. For example, if new enemies target him because of his powerful Sharingan, he'll need to find ways to outwit them and protect those he cares about. This will surely contribute to his character growth.
Naruto would become more introspective. The power of the eternal mangekyou sharingan often comes with a lot of emotional baggage in the Naruto universe. So Naruto might start to question more about his own identity and his place in the ninja world. He might also become more cautious as he realizes the great power he now holds and the potential for misuse.
Well, Naruto having the Mangekyou Sharingan and Rinnegan in fanfiction would change him a great deal. His character development would involve a lot of self - discovery. He'd be constantly exploring the limits of these powers, which would take him away from his home village more often. This would make him miss his friends and family, adding a new layer of emotion to his character. He'd also have to deal with the envy and fear of others who might see him as a threat because of his powerful eyes. But through it all, Naruto would strive to use these powers for the greater good, and this would shape him into a more mature and respected ninja in the fanfiction world.
Naruto would become more introspective. The Mangekyou Sharingan often comes with a heavy burden and dark secrets. He'd have to deal with the new powers and the potential corruption they bring. For example, he might start to question his own motives more often.
One interesting concept could be how Kakashi uses the eternal Mangekyou Sharingan's unique powers in new and unexpected ways. For example, he might be able to create more complex illusions or have enhanced teleportation abilities.
His relationships would also change. Some of his friends might be a bit wary of him now that he has such a powerful and somewhat feared ability. Naruto would have to work hard to show them that he's still the same Naruto. At the same time, he could form new alliances with those who are interested in his new power or who can help him understand it better. He might also be more isolated at times as he delves deeper into mastering the Sharingan, which would be a big change from his usually outgoing and social self.
Naruto's fighting style would evolve significantly. He would no longer just rely on his brute strength and the Nine - Tails' chakra. With the Eternal Mangekyou Sharingan, he could use powerful genjutsu and ninjutsu unique to the Sharingan. He might start to use more stealth and precision in his attacks. His training would also change as he has to master the new abilities. He would probably study Uchiha history and techniques more, which would make him more well - rounded as a ninja. This new power would also bring out a more serious side of Naruto, as he now has the responsibility of using such a powerful ability for the good of the village and the ninja world.
Sakura's character would develop in terms of her combat skills. The Sharingan would allow her to analyze her opponents' moves more quickly and accurately. This would also boost her self - esteem as she would no longer be seen as just a support ninja. She would start to take on more dangerous missions and grow as a leader within her team. For example, she could use the Sharingan to see through genjutsu more easily during battles, which would give her an edge. Additionally, she might develop a new sense of pride in her abilities that was not there before, as she now has a unique power that few others possess.