Well, it could be really chaotic. Naruto already has a powerful force within him with the Nine - Tails. If Sans was sealed in him too, Naruto might gain Sans' unique abilities like his teleportation and bone attacks. His fighting style would become extremely unpredictable, mixing ninja techniques with Sans' skeletal powers.
The ninja world would be in shock. The Hidden Villages would be very cautious around Naruto. They might see him as an even greater threat or an unknown entity. His friends, like Sakura and Sasuke, would have to adjust to this new Naruto and learn how to fight alongside him with his new powers.
In a fanfiction with Naruto having Frieza sealed in him, there would be a clash of cultures too. Naruto comes from a world of ninjas with honor and teamwork, while Frieza is a tyrant from a universe where power rules all. Naruto would have to find a way to balance Frieza's power without losing his own values. His training would take a whole new turn as he tries to master Frieza's power. And there could be a lot of internal conflict as Naruto battles with Frieza's consciousness inside him, trying not to let Frieza take over his body.
Well, he might gain some spooky powers. Maybe he could use the Shinigami's abilities to sense death or even communicate with the dead. It could also put him in a really dangerous situation, as the Shinigami's power might be too much for him to control at first.
Maybe it's an ice - dragon. This would be an interesting contrast to Naruto's usual warm - hearted personality. The ice - dragon's power could be used in creative ways in battles, like freezing opponents or creating ice - based defenses.
The story could progress with Naruto facing new and more powerful enemies. With Frieza's power, he might attract the attention of stronger villains. His friends might also be in more danger as Naruto's new power makes him a bigger target.
This could have a profound impact on Naruto's character. Firstly, he might feel an added pressure to live up to Minato's legacy. Since Minato was highly respected, Naruto would strive to be as great. Also, Minato's presence could act as a guiding force, influencing Naruto's values and his approach to relationships. For example, Minato might offer advice on how to handle his friends better or how to deal with the village politics through their mental connection. This would lead to a more mature and well - rounded Naruto.
Well, it could greatly enhance his physical strength. With a dragon's power, Naruto might be able to deliver more powerful punches and kicks. His speed could also increase as the dragon's energy might boost his reflexes. And his chakra, which is already quite strong, could be amplified to new levels, allowing him to perform more powerful jutsus with ease.
Well, it could enhance his powers in many ways. The Shinigami is a powerful entity, so Naruto might gain some death - related abilities. Maybe he could sense the presence of death more acutely, or have the power to temporarily 'kill' an opponent's abilities. For example, he could send out a sort of death - like energy that freezes an enemy's chakra for a short time.
His personality might become more somber. Having the Shinigami inside him could make him more aware of death and the finality of things. He might be less reckless in battles as he now has a constant reminder of the seriousness of death.