It could be a descendant of a rival family to the Peverells. This person might be jealous of the power and secrets that the Peverell family held and wants to stop Harry from uncovering them. They could try to manipulate events to their advantage and create obstacles for Harry.
Perhaps Voldemort could still be the main antagonist, but in a different way. Ignotus Peverell's secrets might be the key to finally defeating Voldemort. So Voldemort would do everything in his power to stop Harry from getting to those secrets. He might send his Death Eaters to interfere with Harry's search for Ignotus Peverell - related things.
Well, in such a fanfiction, Harry Potter might discover some long - lost secrets about the Peverell family. Maybe Ignotus Peverell has some hidden magic or knowledge that could help Harry in his fight against Voldemort. For example, he could find a powerful spell or artifact that was created by Ignotus.
Ignotus Peverell himself can be considered the best character in many of these fanfictions. Since he has such a mysterious past and his connection to the Resurrection Stone, he offers a lot of room for creative storytelling.
Often, his character is developed by exploring his backstory. Writers might give details about his family, his upbringing, and what led him to create or obtain the Deathly Hallows. This helps to build a more complex and three - dimensional character.
Well, in many fanfictions, Ignotus Peverell can be portrayed as a very mysterious figure. His connection to the Deathly Hallows is often explored in greater depth. For example, some fanfictions might delve into his life before the creation of the Hallows, his relationships with his brothers, and how his actions ultimately led to the legend we know in the original Harry Potter series.
Perhaps a group of pure - blood supremacists could be the main antagonists. They see the Peverell descendant as a threat to their ideas of a pure - blood - only wizarding world. They might try to undermine the descendant at every turn, spreading false rumors and trying to isolate them from the rest of the wizarding community.
One interesting 'Harry Potter Ignotus Peverell' fanfiction could be one where Ignotus Peverell's early life is explored in detail. It might show how he came to possess the Resurrection Stone and his relationship with his brothers. Another could be a fanfic that weaves a story of how Ignotus Peverell's magic influenced the later events in the wizarding world that Harry Potter was a part of.
It could be a power - hungry alien leader who wants to take over Hogwarts and use its magic for their own empire.
A dark wizard from the Harry Potter universe could be the main antagonist. Maybe a follower of Voldemort who escaped the final battle and found his way to Byakko's world. He sees the power of Byakko and wants to use it for his own evil purposes. He could try to enslave Byakko and use its power to take over both the wizarding world and Byakko's realm.
Most likely, Medusa would be the main antagonist. Her ability to turn people to stone makes her a very dangerous foe for Harry Potter and the other characters in the wizarding world.
It could be a dark fairy who wants to use the power of both the wizarding world and Pixie Hollow for her own evil purposes. She might try to steal the magic from Hogwarts and the pixie dust from Pixie Hollow to become all - powerful.