There are also other characters like Matt Donovan who, despite being human, has a good heart and knowledge of the town. He could potentially be an ally in a different way, like providing information about the town's non - supernatural aspects. And then there's Alaric Saltzman, who has dealt with all kinds of strange things. His experience and wisdom could be valuable to Harry and Teddy.
Maybe they'll encounter the supernatural beings in Mystic Falls. Harry could use his magic to deal with vampires or werewolves in a unique way.
One potential villain could be a rogue Death Eater who escaped justice. This Death Eater might see Teddy as a symbol of the new generation that he wants to destroy. Another could be a jealous wizard who is envious of Teddy's special abilities, like his Metamorphmagus powers, and tries to harm him. Harry would then have to fight these villains to protect Teddy.
The themes of friendship and mentorship are quite prominent. Harry is not only a friend to Teddy but also a mentor, guiding him in the ways of magic and life in general. It also often has the theme of facing one's past, as both Harry and Teddy have some difficult pasts to come to terms with.
Luna Lovegood would be a great addition. Her unique perspective on magic could offer new insights to Teddy. Also, Ron could be included as Harry's best friend. His humorous and sometimes clumsy nature could add some light - hearted moments to the story.
Hermione and Ron would probably be there. They are Harry's best friends, so they might be like aunt and uncle to Teddy. They could help Harry out with raising Teddy, like Hermione giving educational advice.
One challenge could be the Time - Turner rules. If they are using a Time - Turner, they need to be very careful not to break any of the laws regarding time travel. For example, they can't be seen by their past selves or make significant changes that would disrupt the future they come from. Another challenge is the danger of the time period they visit. If they go to a time when Voldemort was active, they are at great risk of being detected by Death Eaters.
Because Teddy is an orphan. Harry, having been an orphan himself, knows the hardships. So he feels responsible for protecting Teddy.
One possible reason could be to protect Teddy. Maybe there are some threats in England that Harry wants to keep Teddy away from. For example, there could be some dark wizards or dangerous magical creatures that target Teddy for some reason.
In fanfiction, Harry might be protective of Teddy because Teddy is Remus and Tonks' son. Harry has a strong sense of loyalty and he may feel a great responsibility towards Teddy as he lost his parents. Also, Harry has his own experience of growing up without parents, so he doesn't want Teddy to go through any hardships alone.
Obviously, Harry and Teddy are the main characters. Harry, who is from the well - known Harry Potter series, and Teddy, who is an important character in that universe as well. There might be other secondary characters depending on the specific plot of this fanfiction, but the central focus would be on Harry and Teddy's relationship.