In this fanfiction, it could be that the future has a new Dark Lord. The Marauders are brought forward in time to stop this new threat. They face challenges like understanding the new forms of magic and technology that the future Dark Lord has harnessed. They also have to deal with the fact that the future wizarding world has different social and political structures. They might start by infiltrating the Dark Lord's lair using their Marauder's Map - like skills, but find that the map doesn't work as well in the future, leading to all sorts of interesting and dangerous situations.
Obviously, the Marauders themselves - James Potter, Sirius Black, Remus Lupin and Peter Pettigrew would be the main characters. They are the ones 'meeting' the future after all.
When the Marauders travel to the future in a fanfiction, they may meet the students of Hogwarts in that future time. These students could be very different from the ones they knew in their own time. The Marauders might also come across future wizards and witches who are experts in new areas of magic that the Marauders have never even heard of. Additionally, they could meet people who are working on projects to preserve the history of the wizarding world, and these people might be very excited to meet the Marauders who are a significant part of that history.
Obviously, the Marauders which include James Potter, Sirius Black, Remus Lupin, and Peter Pettigrew. And then there are the Evans family members. Most likely Lily Evans, who is quite important as she has her own story arc and connection to the Marauders, especially James. There might also be other Evans siblings or family members depending on how the fanfiction is written.
The main characters would be the Marauders, which include James Potter, Sirius Black, Remus Lupin, and Peter Pettigrew. And of course, Tonks is also a main character in this fanfiction.
In this fanfiction, perhaps the Marauders would be quite intrigued by Tonks' unique Metamorphmagus ability. They might initially be a bit confused or even amused by how she can change her appearance at will.
Well, it could be a really heartwarming scenario. The marauders might be shocked at first to see how much their grandchildren resemble them or their children. They could share stories of their adventures, passing on their wisdom and perhaps even some magical tricks.
The Marauders meeting Ginny in a fanfiction could lead to all sorts of interesting scenarios. Maybe Ginny is a bit star - struck at first, since the Marauders are sort of legends in the wizarding world. They could exchange stories about Hogwarts. Ginny might tell them about how the school has changed over the years, and the Marauders could regale her with tales of their own school days. It could also be a story about Ginny learning from the Marauders' more unorthodox ways of using magic.
The marauders would probably have to adapt their way of thinking. In the future, the concepts of right and wrong, good and bad might have shifted. They'd need to understand these new perspectives to fit in.
They might be shocked by the advanced technology. For example, seeing flying cars and instant communication devices everywhere could leave them in awe.