In a 'Naruto sent to hell' fanfiction, it could be that Naruto is sent to hell as part of a test. The gods or some powerful entities want to see if he can bring hope and change to the damned souls in hell. So, Naruto starts to teach the souls in hell about friendship, perseverance and the ninja way. He tries to reform the place from within, facing many challenges along the way like powerful hell guards and the dark energy that tries to corrupt him.
In some fanfictions where Naruto is sent to hell, he might face various challenges. He could encounter powerful demons who want to harm him. But Naruto, being a strong - willed character, would likely try to fight his way out. He might also meet some other lost souls in hell and try to help them while finding a way back to the living world.
It could be the Devil or some powerful demon lord in hell. This antagonist would try to keep Naruto trapped in hell and prevent him from escaping. He might see Naruto as a threat to his rule in hell or just enjoy tormenting him.
One possible main antagonist could be the ruler of hell. This powerful being would see Naruto as an intruder and a threat to the order of hell. Another could be a demon who has a vendetta against Naruto for some reason, perhaps because Naruto's positive energy is anathema to the demon's evil nature.
Perhaps Chloe is wrongly judged in some sort of afterlife court and is sent to hell. Once there, she meets other souls who help her realize that there's a conspiracy behind her being sent there. So she starts to fight against the system of hell to prove her innocence.
There could be a group of hellish bureaucrats who are the antagonists. They are the ones who sent Chloe to hell in the first place and are trying to keep her there to maintain the order of hell as they see it. They might not want Chloe to expose the unjust system that exists in hell.
One interesting Naruto and Hell Girl fanfiction could be where Naruto somehow ends up in the world of Hell Girl. Maybe he meets Ai Enma and tries to convince her to use her powers for good in a different way. There could be a plot where Naruto's positive energy starts to influence the dark world of Hell Girl.
In Naruto fanfiction related to Hell, one rule could be that the powers and abilities of characters are often adjusted to fit the Hellish environment. For example, a character might gain the ability to withstand extreme heat or manipulate demonic energy.
Naruto hell fanfiction often has a more horror - themed element compared to regular fanfiction. The settings are filled with fire, brimstone, and other hellish features. It also allows for different interpretations of the characters' personalities. In a hellish situation, Naruto might show more of his desperate and survival - instinct side rather than his more upbeat and hopeful side in regular fanfiction.
Well, Naruto might find allies among the outcasts of the new dimension. People who don't fit in with the mainstream society but have unique powers or skills. They could see Naruto as a kindred spirit and join forces with him. Also, if there are any beings in the new dimension that oppose the forces that brought Naruto there, they could be his allies. They might have their own reasons for wanting to help Naruto, like using his power to overthrow a tyrant in their dimension.