Perhaps Harry would take Tom on a journey through Hogwarts' history. Show him how the school has been a place of both good and bad magic, and how students in the past have made choices that shaped the wizarding world. This could make Tom see that his actions can have a long - lasting impact on the future of the wizarding community.
A lot could occur. Harry might try to instill in Tom the importance of forgiveness. Given that Harry has forgiven many of his enemies, he could explain to Tom that holding grudges and seeking revenge only leads to more pain and destruction. For example, when he forgave Snape in the end.
Harry could also teach Tom about love. Harry has experienced love in many forms, from the love of his parents to the love of his friends. He might convey to Tom that love is the most powerful magic of all, and that without it, any power gained through dark magic is ultimately empty.
One possible plot could be that Harry, using his knowledge of love and friendship, tries to teach Tom about the power of positive emotions. He might show Tom how his own journey was shaped by the love of his friends and family, in contrast to Tom's more solitary and power - hungry path. Maybe Harry takes Tom to Hogwarts in a time - travel like scenario and shows him the true meaning of the houses, not just the pursuit of power within Slytherin.
Maybe Harry would teach Tom about the consequences of dark magic. Since Harry has faced Voldemort multiple times and seen the destruction caused by dark spells. He could use these real - life (well, in the wizarding world) examples to make Tom understand that there are other paths in magic that are more positive and life - affirming.
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.
If Harry Potter teaches at McKinley in fanfiction, it would be a total chaos in a good way. The students there are used to a normal school life. Harry would bring in Quidditch and the students would be thrilled. He could also teach them about the different magical creatures, which would be a whole new world for them. And of course, his Defense Against the Dark Arts classes would be legendary.
One reason could be that he wants to find new ways to manipulate the story. Since fanfiction can be so diverse, he might be looking for ideas that he can use to his advantage. Another reason could be a strange form of entertainment. Even though he's a dark character, he could still find the creativity in fanfiction amusing or useful in some way. And maybe, just maybe, he has a hidden love for the world of Harry Potter that he doesn't show in the original story.
As the teaching progresses, they could develop a sort of mentor - mentee relationship. Harry would be constantly trying to steer Tom away from the Dark Arts, while Tom would be trying to learn as much as he can from Harry. However, there would always be an underlying tension because of Tom's future as Voldemort. Their relationship might be a complex dance of trust and suspicion.
In a Tom Riddle x Reader fanfiction, they could meet in Hogwarts. Maybe the reader is a new student and catches Tom's attention with their unique magical abilities. This could lead to a series of interactions where Tom tries to figure out the reader's secrets.
Well, one possibility is that it would create a huge conflict within the wizarding world. Harry is seen as a hero and Tom Riddle (Voldemort) is the ultimate villain. His daughter would be a very controversial figure. Harry might face a lot of opposition from his friends and the wizarding community at large.
One possible plot twist could be that Tom Riddle discovers Harry has a hidden power that he didn't expect. Maybe Harry has the ability to resist Riddle's mind - control spells in a unique way. This could lead to a battle of wills between them where Harry tries to outwit Riddle while being held captive.
One possibility could be a story of internal conflict for Harry. He might struggle with the dark heritage from Tom Riddle while trying to uphold the values of the wizarding world he has grown to love. He could constantly battle his own darker instincts that come from being Voldemort's (Tom Riddle) son. For example, he might have an in - built talent for Parseltongue that he has to learn to control and use for good instead of evil.