One possible consequence is new and unexpected abilities. For instance, if his DNA is changed to incorporate some sort of spirit energy, he could gain the ability to communicate with the dead. Another consequence could be changes in his appearance, like his hair color or eye color changing. This can also lead to social isolation as his friends might not recognize him at first.
One consequence could be new powers. If he absorbs the DNA of a powerful ninja, he might gain their unique abilities. For example, if it's from a ninja with ice - based powers, Naruto could potentially start to use ice - based jutsu. Another consequence could be changes in his appearance. The absorbed DNA might have physical traits that start to show up on Naruto, like different eye color or hair texture.
Naruto's view of himself and his purpose in life could also change. He might start to question his identity as the Jinchuuriki of the Nine - Tails. With new DNA - based powers, he could feel like he has a different role to play in the ninja world. He might explore new ways to use his powers for the greater good, which would be a significant development in his character.
One idea could be that Naruto gains new powers. For example, if his DNA was changed to have some Uchiha traits, he might be able to use Sharingan - like abilities. This could completely change the way he fights and strategizes in battles.
One possible plot development could be Naruto facing internal struggles. He has always been Naruto Uzumaki, and now with Madara's DNA, he might question his identity. Another could be that the village starts to view him differently. Some might fear his newfound power, while others might see him as a potential threat. There could also be a plot where Naruto has to learn to control the new powers that come with Madara's DNA quickly, as an enemy emerges who can only be defeated with these new abilities.
One consequence could be that his friends are filled with grief and a strong desire for revenge. They might go on a rampage to find the ones responsible for Naruto's death.
One possible consequence could be that Naruto is ostracized by some in the ninja world. Since controlling blood is a rather strange and perhaps 'creepy' ability to some, they might view him with suspicion or fear. This could lead to him having to prove himself more often in battles and interactions.
His reputation in the ninja world could be damaged. If Padme spreads false information or reveals his secrets, other ninja might view Naruto differently. They could see him as a liability or a threat. This could lead to him being isolated in the ninja community, and he might have to fight harder to prove himself again.
If his education is sabotaged, Naruto may also face difficulties in understanding the complex political and social aspects of the ninja world. This could lead to him making wrong decisions or being easily manipulated by others who are more informed. He might struggle to form alliances or navigate the power dynamics within the Hidden Leaf Village and among other ninja villages. Moreover, his relationships with his peers could be affected as they might progress faster in their training while he lags behind due to the sabotaged education.
One possible consequence could be that Naruto's body takes a huge toll. Since Kurama is such a powerful entity, summoning him might drain Naruto's chakra to a dangerous level, leaving him vulnerable after the summon. In some fanfictions, he might even pass out immediately after Kurama is summoned.
His relationship with Jiraiya could be affected. Jiraiya has a strong connection with the toads, and if Naruto hates toads, it could create a rift between him and his mentor. This could lead to Naruto losing an important source of guidance and support in the fanfiction.