There could be all sorts of things. Maybe there are magical creatures like fairies or elves that can either help or hinder his journey. There might also be hidden treasures guarded by some fierce beasts. Or it could be a place full of illusions that test his mental strength.
It could be a magic item. Maybe a wand that has the power to grant wishes.
It could be a wild animal that we haven't seen yet. Maybe a large, nocturnal predator like a panther or a wolf - their growls can be quite strange and menacing.
The scariest part could be the feeling of isolation. Just like in the example of the girl trapped in a room with the dog blocking the exit. She is alone with this unpredictable animal, and there's no one to help her. This sense of being completely cut off from the outside world can be truly terrifying.
The main character in 'anne the continuing story' is Anne. However, we don't have any information about what she's like. Is she young or old? Is she kind - hearted or a bit of a troublemaker? These are all things we can only guess at until we learn more about the story. She could be a strong - willed individual, determined to make her mark in the world, or a more timid person who has to find her courage as the story progresses.
The main character is most likely an individual with a problem related to his left foot. This person might be someone who has been underestimated or marginalized because of this disability. However, he or she has unique qualities that help him or her rise above the situation. He or she could be from any walk of life, but the story of his or her left foot becomes a symbol of his or her journey through life, full of obstacles and triumphs.
Imagine a woman who lives in an old mansion on the outskirts of the city. She always wears black and has a locked room in her house that no one has ever seen inside. She is often seen whispering to someone who is not there. Her mysterious back story could involve a lost love, a family curse, or a dark secret from her past. There are so many possibilities that can make the audience curious and want to know more about her.
The main character in the 'I passed through a dark forest story' could be a wizard or a magical being. Maybe they are on a journey to collect rare ingredients for a powerful spell and the dark forest is the only place to find them. The character would then have to use their magic skills to deal with the perils of the forest, such as dark magic that lingers among the trees or enchanted beasts that guard the precious ingredients.
πI recommend you the book "Otherworld Space". The plot is similar to what you said! The main character had also transmigrated to the other world. He was responsible for protecting the laboratory in the other world, but at the same time, there was a barrier that prevented people from the outside world from entering. The beauty that the main character met was the Elven Queen from another world. The interaction between the two was also very interesting. I hope you like my recommendation, Mwah ~π
Perhaps some of the other ninja villages see Naruto as a potential danger in the future, so they manage to infiltrate Konoha and make it seem like Naruto has committed a great crime, resulting in him being left in the forest. In this case, the main antagonist would be the ninja from the other villages.
It could be a young girl with special powers. For example, she might be able to communicate with plants, which would be very useful in a forest adventure as the plants could give her hints or help her avoid danger.