In some fanfictions, Harry might use extremely powerful and ancient magic. Maybe he discovers a long - lost spell during his adventures that has the power to reverse death. For example, he could find a spell hidden in a forgotten corner of the Hogwarts library that was created by a powerful wizard in the past but was deemed too dangerous to be used.
In fanfiction, when Harry Potter meets his parents, it could be an extremely emotional encounter. He might finally get the chance to hug them and feel the love and warmth of a family he's always longed for. His parents could offer him advice on how to deal with Voldemort and the challenges at Hogwarts. Maybe they'd share some long - forgotten family secrets or magic spells with him. It would be a moment of great joy and connection for Harry, filling the void of his orphaned life.
One possible reason could be that he might feel abandoned. Growing up without them, he could resent the fact that they left him an orphan. He might think that if they were really so great, they would have found a way to survive and be there for him.
Yes, there might be some extremely dark and out - of - canon fanfictions out there with such a disturbing premise, but it goes against the general nature of the original story where Harry's parents loved him deeply. However, in the vast world of fanfiction, people can create all kinds of strange and often inappropriate scenarios.
On a more magical level, reviving the dead is against the natural order of things in the wizarding world. This could attract unwanted attention from magical authorities or even dark forces. Some might see Harry's act as a dangerous precedent and try to either stop him or use his new - found power for their own evil purposes.
He learned a great deal from Hagrid. Hagrid was the one who first told Harry about his parents' death and how they were killed by Voldemort. Hagrid also gave Harry the photo album which showed pictures of his parents and their friends.
The plot would change drastically. Harry would not be living with the Dursleys, so there would be no need for him to escape that horrible situation. Voldemort might have a harder time targeting him as his parents would be on high alert. There would be no letter - hunting drama. Also, his relationship with Snape would be different as his father was Snape's rival. His parents could have taught him some advanced magic from a young age, which would make him stand out at Hogwarts in a different way than in the original story.
One possible reason could be a misunderstanding. Maybe he discovers some secrets about his parents that he misinterprets. For example, if he finds out they were involved in some dangerous or morally ambiguous activities in their youth that he doesn't fully understand at first.