Naruto's character might develop a sense of responsibility on a much larger scale. Since he has Kaguya's power, he would feel the need to protect the entire world in a more absolute way. He could become more solemn and less carefree as he realizes the magnitude of the power he now holds. He may also start to study more about the ancient history related to Kaguya to better understand his new powers.
When Naruto absorbs Kaguya in a fanfic, his character development could be complex. He might struggle with the new power within him. On one hand, he wants to use it for good, but on the other hand, he might be afraid of losing himself. His relationships with Sasuke and other friends could change. For example, Sasuke might be more on guard around him. Naruto may also have to deal with the moral implications of having such a powerful and potentially dangerous ability. He would need to constantly remind himself of his original values and not let the power corrupt him.
After absorbing the Juubi in fanfic, Naruto's character may become more confident. He has so much power now that he knows he can handle most situations. His sense of responsibility would also grow as he has to control such a huge power.
When Naruto absorbs the Shinju in fanfiction, his character development can take many forms. He could become more isolated as others may fear his new power. But at the same time, he might also strive to prove that he's still the same Naruto at heart. He may start to explore the deeper meaning of his power and how it can be used for good, which would lead to a more mature and introspective side of his character.
After absorbing Kami in fanfiction, Naruto's character development can be quite complex. He could start to question his own identity and what it means to have such power. This internal conflict can lead to him becoming more empathetic towards others who are also dealing with power or identity issues. He may also become more cautious in using his new abilities, as he realizes the potential consequences of misusing the power of Kami.
The story could develop with the ninja world exploring new forms of ninjutsu or chakra control now that Kaguya's influence is no more. For example, they might discover new ways to harness natural energy without the fear of it being corrupted by Kaguya's power.
After absorbing Kronos, Percy's character could develop in several ways. He could become more confident in his abilities due to the extra power, but also more cautious as he realizes the potential danger of what he's absorbed. His relationships with his friends and family might change. He could become more of a loner as he tries to figure out how to control the new power and keep it from corrupting him. His sense of responsibility might also grow as he now has the power to cause great harm or do great good.
After absorbing Gaea in fanfiction, Percy's character could become more complex. He might struggle with the new power and the responsibility that comes with it. He may become more withdrawn as he tries to figure out how to control this new part of himself.
His view of the world could change. Dark Naruto might have carried some resentment or a different perspective on the ninja world. After absorption, Naruto may start to see things from a more cynical angle at first. However, as he grows and reconciles with this new part of himself, he could end up with a more balanced view that takes into account both the positive and negative aspects of the ninja world. This could lead to him making different decisions in how he approaches problems and interacts with others.
His sense of responsibility would likely increase exponentially. Since he now has the power to potentially change the past and shape the future, he would feel a great burden. This could lead to him becoming more of a strategic thinker, rather than just relying on his brute strength and determination. He would also have to deal with the moral implications of using his new powers, which would further shape his character.
He may become more confident. With the new powers from the Ten - Tails, Naruto would know he has an edge in battles, and this could boost his self - assurance.
He becomes more confident. With the power of the Infinity Stones, Naruto knows he has an edge over his enemies. He's no longer just the underdog ninja trying to prove himself.