Harry Potter himself would be very interesting. Since he has already faced the fully - formed Voldemort in his own time, seeing Tom Riddle in the past and understanding how he became who he is could be a great character arc for Harry. He could be conflicted between his hatred for Voldemort and his pity for the young Tom who still has a chance at redemption.
Dumbledore could be an interesting focus. If Harry travels back in time and teams up with the young Dumbledore, we could see how Dumbledore reacts to the presence of Harry from the future. His wisdom and knowledge could play a crucial role in dealing with Tom Riddle. Also, exploring Dumbledore's past and how he dealt with the early signs of Tom's darkness could add depth to his character in this fanfiction.
Harry would be really interesting. He has to step into the role of a teacher, which is quite different from his usual role as a student or a hero. He has to figure out how to communicate with Tom, who is essentially the most evil wizard in history. Harry's own experiences with Voldemort give him a unique perspective, and seeing how he uses that to try and teach Tom would be fascinating.
Definitely Harry Potter himself. His journey through time could be a way for him to gain more understanding of his parents and the events that led to their deaths. He could also try to change some things in the past to make the present better. For example, he could try to prevent Voldemort from ever becoming so powerful in the first place. And seeing Harry interact with the people from the past, like his grandparents or young Dumbledore, would be really fascinating.
Hermione would be really interesting. She's so intelligent and studious. If she traveled back in time, she could use her knowledge of magic history and spells to make a big impact. For example, she might be able to help the Order of the Phoenix in new ways during the First Wizarding War or she could introduce some modern magical concepts to the wizards of the past.
Dumbledore would be really interesting. He has so much knowledge about Tom Riddle's past and his transformation into Voldemort. His presence could add a lot of wisdom and guidance in the story. For example, he could be the one to help Harry understand Tom's motives better, or he could try to intervene in their meetings to ensure that Harry doesn't make any dangerous mistakes.
Hermione Granger is often a popular character. She can use her intelligence to figure out the implications of time travel and help Harry or deal with Tom Riddle in some way. For instance, she might research spells to counteract any dark magic that Riddle tries to use during their time - traveling encounters.
Tom Riddle might be very suspicious at first. He is a very intelligent and cautious person. He would likely view time travelers as a threat to his plans or as a strange new phenomenon that he wants to control. So, he could start by trying to figure out their motives and how they managed to travel through time.
One idea could be that Harry accidentally travels back in time and meets a young Tom Riddle before he fully turns evil. He tries to change Tom's path by befriending him and showing him kindness, which leads to a series of events where the future of the wizarding world starts to change in unexpected ways.
The exploration of their relationship is also a major theme. In many fanfictions, Harry tries to understand Tom Riddle, and they develop a complex bond that may range from enmity to a strange kind of understanding. For example, in some stories, they might start to see each other's points of view, which changes their relationship dynamics. This is especially interesting considering their roles in the original series. They are enemies, but time - travel gives an opportunity to rewrite that narrative in a way.
Mr. Incredible would be really interesting. He's already a strong and experienced hero. If he travels through time, he could use his brute strength in different historical contexts. He might have to adapt his fighting style in eras with different technologies or combat techniques. For example, in a medieval - like time period, he'd have to rely more on his physical skills without his modern gadgets. Also, seeing how he reacts to meeting his ancestors or versions of himself from different times would add depth to the story.
Reaper could also be an interesting focus. His dark and mysterious past could be explored further through time travel. He could go back to the time when he was still Gabriel Reyes, before the transformation. This could show the events that led to his current state, and perhaps in a time travel scenario, he could even have a chance to change his fate. It would be a story full of drama, mystery and action as he grapples with his past self and the decisions that led him to become Reaper.