At first, he may be in disbelief. But as he starts to understand what he's seeing, he could become solemn. He realizes the weight of the future and the responsibility he may have to shape it in a positive way. He might also feel a bit of fear, especially if he sees the loss of his friends or loved ones. But overall, his Gryffindor courage would likely kick in, and he'd start to think about how to face whatever the future holds.
Well, if Harry goes back in time, his actions could have a huge impact on the future. For example, if he saves a character who was supposed to die, it could change the entire story. Maybe he saves Cedric Diggory in the Triwizard Tournament earlier than he should have. This could lead to Cedric having a major role in the fight against Voldemort later. Also, if he changes the relationships between characters in the past, like making Snape and Lily closer friends, it could change Snape's attitude towards Harry in the future.
In a Harry Potter fanfic where past meets future, it often works through time - travel magic. For example, a character might use a Time - Turner or some other magical device to journey from the present or future to the past. This can create all sorts of interesting scenarios. They could meet their younger selves, or change events that were thought to be set in stone. It also allows for crossovers between different generations of characters, like Harry meeting his parents when they were at Hogwarts. This kind of plot device can bring new perspectives to the well - known Harry Potter universe and open up a whole new world of storytelling possibilities.
Harry might be a bit skeptical at first. He would question whether this is really his future self or some kind of trick. But as the future self starts to share some personal details or knowledge only Harry would know, he would start to believe. Then, he could become eager to learn from his future self, asking all kinds of questions about his future, his friends, and his role in the wizarding world.
In 'past meets future' Harry Potter fanfics, a major theme is the clash of different magical cultures. The future might have a more evolved form of magic, and when it meets the past, there are conflicts and also new understandings. Another popular theme is the power of friendship across time. Characters from different time periods form bonds that help them overcome challenges. And then there's the theme of self - discovery. A character going to the past or future might learn something new about themselves that they wouldn't have known otherwise.
The idea of past villains resurfacing in the future in a different form is also fascinating. Maybe Voldemort's ideology gets reincarnated in a new dark wizard, and the heroes from the past and present have to team up to defeat this new threat. This would show how the past and future are intertwined in the fight against evil in the wizarding world.
He could be shocked. Maybe there are some fanfictions that take a very dark turn or have unexpected pairings that he never thought of. He'd probably need some time to process such strange ideas. And he might also be curious to see how far the creativity of the fans can go. He might even get some new ideas about his own life from reading some of the more imaginative fanfictions.
The older characters such as Kakashi would be cautious. They would recognize Naruto but also be worried about the implications of someone from the future being in the present. They would want to know if his presence could change the future in a negative way. For example, they might fear that his actions could lead to the earlier awakening of a powerful enemy. As for the villains, they might see future Naruto as a threat and try to eliminate him as soon as possible. Orochimaru, for instance, would be very interested in Naruto's future powers and might try to capture him to study. And the new generation of ninja in the past would look up to future Naruto, seeing him as a symbol of what they could become.
One common theme is time - travel. Since it's about past and future, many fanfictions play around with characters going back in time or forward. Another theme could be the alteration of the original plot. For example, if a character from the past sees the future, they might try to change certain events that lead to that future. Also, there's often a theme of self - discovery. As characters interact with different versions of themselves or the wizarding world from different times, they learn more about who they are and their place in the magical universe.
Hermione Granger is also a likely character. Her intelligence and love for knowledge could lead her to discover a way to bridge the past and the future. She might use her Time - Turner knowledge or find some new magical method. And she could play a key role in helping past characters adapt to the future or vice versa.