Dean could face problems related to the timeline itself. His presence in the future might accidentally disrupt the course of events and create unforeseen consequences. He would need to be extremely careful not to cause any major changes that could have a negative impact on the future or his own past.
One challenge could be the cultural shock. The future society might have very different norms, values, and social structures. Dean, coming from his own time, would have to quickly adapt to avoid standing out or getting into trouble.
Another issue is that he might not be able to use his usual hunting skills effectively. If the future has new types of threats or different ways of dealing with danger, Dean would need to learn new techniques. For instance, if the future has advanced weaponry that he's not familiar with, he would be at a disadvantage in a fight.
They could face technological challenges. The future's technology might be so advanced that they can't understand or operate it, like flying cars or energy shields.
A big challenge would be dealing with the lack of modern technology and conveniences. There would be no cell phones to call for help or the internet to look up information. In a time before modern medicine, getting sick could also be a major issue as there are no antibiotics or advanced medical treatments. Also, if you travel to a time of war or unrest, simply staying alive and out of harm's way would be a constant struggle.
One challenge could be loneliness. Without companions, the boy may feel isolated and long for human connection. For example, in 'The Adventures of Huckleberry Finn', Huck sometimes misses having a proper friend to talk to.
One challenge could be dealing with the new - found attention. Suddenly, everyone is looking at you, expecting you to keep performing at that high level. Another is the pressure to maintain the success. You might be worried about not being able to top again in the next competition.
One challenge could be time management. Naruto is always so busy with his ninja duties, protecting the village and going on missions. Finding the time to sit down and write would be tough. Also, he might struggle with grammar and spelling since his ninja training didn't really focus on that.
One challenge could be gaining the trust of the Root members. Since Root has a history of being a secretive and somewhat feared organization, the members might be skeptical of Naruto's leadership. They're used to a more authoritarian style, and Naruto's more open and friendly approach could be met with resistance.
Mako might face vocabulary challenges. Fanfiction often contains unique words or terms specific to the fandom. Also, understanding different writing styles can be difficult as fanfiction varies greatly in style. Another challenge could be following complex plotlines that are sometimes created in fanfiction, especially those that deviate from the original source material.
One challenge is spelling errors. Dyslexia can make it difficult to spell words correctly, which might be a hindrance in writing fanfiction. Another is grammar. They may have trouble with proper sentence structure. Also, organizing their thoughts into a coherent story can be tough as dyslexia sometimes affects the ability to sequence information.
They might face the risk of changing the future in ways they don't expect. For example, if they accidentally prevent an important event from happening, it could have a huge impact on their own present. Also, they could encounter past versions of themselves or their enemies, which could lead to some really confusing and dangerous situations.
One challenge Clark might face is changing the future too much. If he alters significant events, it could have unforeseen consequences. For example, if he saves someone who was supposed to die, that person's actions in the future might cause more harm than good. Another challenge is dealing with his younger self. He has to be careful not to expose his identity or give away too much information. Also, he might face challenges in terms of fitting into the time period. The technology and social norms of the past could be very different from what he's used to in his own time.