It's also possible that there are characters from the original work (if this is a fanfiction based on something) that make appearances. They could play important roles in Naryo's journey, either by directly assisting or by creating situations that Naryo has to deal with in order to get to the other side.
Well, without actually reading the specific 'Naryo Getting to the Other Side' fanfiction, it could be about a character named Naryo's journey to reach another place. Maybe it's a physical place like a new land or a metaphorical place like a new state of mind. It could involve various challenges and adventures along the way.
Sasuke could also be a main character. He may play a role in either helping or hindering Naruto's journey in this new side. Their relationship might be explored in a new light, with new challenges and reconciliations.
The main characters in 'the other side miraculous ladybug fanfiction' are probably Ladybug and Cat Noir as they are the main protagonists in the original series. But it could also feature characters like Alya or Nino in different roles. Maybe Alya has a Miraculous of her own and is a key part of the 'other side' story. Nino could also be involved in some new and unexpected way, like being part of a resistance group against an evil force on this 'other side'.
Most likely, Harry Potter would be one of the main characters. Since it's based on the Harry Potter series, he would probably be central to the story, perhaps leading the fight against the evils of this 'hell' side.
I'm not sure specifically as I haven't read the novel in detail, but typically there would be a protagonist who is likely at the center of the story. Maybe someone who is on a quest to uncover the mysteries on the other side of darkness.
A unicorn from the main pony world who gets lost in the other side could be a main character. Their magical abilities might be different or not work as well in the other side, leading to an interesting story of adaptation.
I don't know for sure, but probably the boy himself is a main character. There might also be some people he meets on 'the other side' who are important.
There might be a character who represents the upper class, like a noble or a wealthy merchant. This character could be used to show the power dynamics and the privileges of that social stratum during the historical period depicted in 'On the Other Side of the Hill'. They could be involved in political intrigue or have a role in shaping the economic situation of the area.
As I don't know the exact story, I can't say for sure who the main characters are. It could be an individual adventurer, a group of mountaineers, or local people who live near the mountain.
I'm not sure specifically as we don't have the full story here. But it could be a person living on one side of the wall who is curious about the other side. Maybe there's an old man or a young child.