Maybe it could be a half - blood wizard who was raised in seclusion. He discovers his connection to Sauron through some ancient family heirloom or a strange dream. This character could be conflicted between the dark power he has inherited and the good he sees in the wizarding world. Another option could be a former Death Eater who, after Voldemort's fall, discovers that he has a deeper and more ancient connection to Sauron and decides to pursue that power.
One potential character could be a new student who arrives at Hogwarts with a mysterious past. He shows extraordinary magical abilities that seem a bit too dark for the normal wizarding world. Another could be a distant relative of Draco Malfoy. Since the Malfoys have a history with the dark arts, it wouldn't be too far - fetched for one of them to be revealed as the heir of Sauron. Or perhaps an old wizard who has been in hiding for centuries and resurfaces as the heir of Sauron.
It could be a previously unknown character, like a distant relative of one of the main families in the Harry Potter series. Maybe a long - lost cousin of the Weasleys or a descendant of one of the founders of Hogwarts that has been living in hiding.
It could be a new character introduced specifically for this fanfiction. Maybe a transfer student from a far - off wizarding school with a mysterious Roman heritage.
Harry Potter himself could be a potential candidate. Given his unique connection to Voldemort and his own powerful magic, it's not a stretch to imagine him being the heir of some long - forgotten magic. Another could be Hermione. Her intelligence and thirst for knowledge could be signs that she has a deeper connection to a magical heritage. Ron could also be a candidate, as his family has a long history in the wizarding world and there could be some hidden magic in his bloodline.
Another possibility is a student at Hogwarts who has always been in the background. A shy or overlooked character who suddenly discovers that they are the unknown heir. For instance, Neville Longbottom could be an interesting choice. He has shown great courage and growth throughout the series, and if he were revealed as the heir, it would give his character a whole new level of importance.
Perhaps it could be a long - lost relative of Harry Potter himself. Since Harry has so many mysterious aspects to his own story, it wouldn't be too far - fetched for a relative of his to be the heir. Another possibility is a character from one of the minor wizarding families that has been overlooked in the original series but actually has a strong connection to the swords.
An unknown wizard from a far - off land could be a thief in Harry Potter fanfiction. This wizard could come to Hogwarts or the wizarding world of Britain with the intention of stealing unique magical items that are not found in their own land. They would bring a sense of mystery and a new cultural perspective to the story.
Perhaps it could be an already existing character from the Harry Potter series who is revealed to have Uzumaki blood. For example, Neville Longbottom could be secretly an heir of Uzumaki. His clumsiness could be a cover for his latent Uzumaki powers which could be awakened during a crucial moment in the story.
Perhaps it's a character from a minor magical family that was thought to be extinct. Their heir could have powers that are a combination of ancient magic that was thought to be lost. They might have the ability to communicate with magical creatures in a way that no human has been able to do before, which would make them very powerful in the eyes of both those who want to protect magical creatures and those who want to use them for their own gain.
It could be Harry Potter himself. Since he has so many special qualities and a deep connection to Hogwarts, he might be revealed as an heir. Maybe he has some latent powers related to one of the founders that haven't been discovered yet.
Bellatrix Lestrange, if she had survived the Battle of Hogwarts. She was extremely powerful and deranged. She could rule the wizarding underworld with an iron fist, using fear and torture to keep her subordinates in line. Her loyalty to Voldemort could be transferred to her own self - serving criminal empire.