Naruto as the king of hell could bring a new order. He would likely use his ninja skills and values. For example, he might create a system where souls are judged based on their actions and intentions during their lifetime, rather than just on their sins. And he would surely try to protect the innocent souls in hell from any unjust treatment.
His rule would probably be fair. Naruto has always been about justice and understanding. He might reform the hell system, making it less cruel and more about rehabilitation for souls.
His magic could be related to his chakra control. Maybe he could turn his chakra into different elements of magic, like fire magic similar to his Fireball Jutsu but with a more magical twist. For example, instead of just a normal fireball, it could be a fireball with runes inscribed on it for extra power.
Naruto's outgoing personality would have a great influence on his rule. He is very friendly and approachable, so the villagers would feel comfortable approaching him with their problems. This would lead to a more connected and trusting relationship between the ruler and the ruled.
If Naruto becomes a Joker fan in the fanfiction, his new look could be really different. He would probably ditch his orange jumpsuit for something more in line with the Joker's style. A long, tattered purple coat perhaps, with some dark makeup around his eyes to give him that menacing look. His shoes could be replaced with some clown - like shoes, and he might carry around a few 'joker - ish' accessories like a deck of cards or a fake flower that sprays water. His overall appearance would be a blend of his ninja - like physique and the Joker's flamboyant and chaotic style.
It could be a result of his own growth and power evolution. Naruto has constantly grown throughout his journey. His chakra, his skills, and his understanding of the world have all expanded. Perhaps his newfound power reaches a level where he is deemed worthy of ruling hell. Maybe he has to pass some sort of trial or overcome a great obstacle in hell itself, and by doing so, he proves himself to be the rightful king.
His friends like Sasuke, Sakura, and Kakashi would surely support him. They have been through a lot together and know Naruto's good heart and leadership potential.
His teaching style might be very hands - on. Naruto is someone who has learned through experience, so he would likely encourage his students to do the same. He would probably tell them stories from his own adventures to make lessons more interesting.
In 'naruto is the ruler of hell fanfiction', Naruto might be in a position where he has to make some really tough decisions. He is used to protecting the living world, but now in hell, the rules are different. He could be trying to reform some of the souls in hell, using his own sense of justice and mercy that he developed in the ninja world.
In fanfiction, Naruto's rule as the 5th Hokage might be full of positive changes. He would probably focus on improving relationships between the different ninja clans in the village. He'd also likely invest a lot in training the new generation of ninjas, using his own experiences to teach them about perseverance and the importance of friendship.
If Naruto becomes like Hashirama in fanfiction, it could mean he has a similar leadership style. Hashirama was known for his charisma and ability to bring people together. Naruto already has those qualities, but it could be enhanced. He could also inherit Hashirama's skills in wood - style jutsu, which would give him a whole new set of abilities in combat and for building things in the village.
In such a fanfiction, Naruto might become a dark and brooding figure. His usual positive traits could be twisted. Maybe he has nightmares that change his perception of the ninja world, leading him to question everything he once believed in. This could result in him having a more cynical view and taking actions that are out of character for the original Naruto, like being more ruthless in battle or distrusting his friends.