Who could be the main antagonist in a 'Harry and Ron not friends fanfiction'?

It could be a dark wizard who has also discovered the secrets of Forks and wants to use the town's unique location or some hidden power there for evil purposes. This dark wizard might see Harry and Ron as threats and try to get rid of them. He could be using dark spells to manipulate the townspeople or cause chaos in Forks.

It could be a jealous student. Maybe there's a Gryffindor who is envious of Creevey's friendship with Harry. This student might spread rumors about Creevey, saying that he's only using Harry for his fame. This causes some tension between Harry and Creevey at first, but they eventually figure out the truth and strengthen their bond in the face of this false accusation.

The antagonist could be a cursed object. This object, which has some dark magic in it, might be found by Harry. And when he interacts with it, it starts to control his actions, leading to him breaking Ron's leg. So, in this case, the cursed object is the source of the trouble and can be considered as the antagonist in the fanfiction.

The Ministry of Magic could also be the main antagonist in this case. If the Ministry is corrupted or under the influence of dark forces, they could manipulate Harry's friends. They might convince his friends that Harry is a danger to the wizarding world order, and his friends, being naive or misinformed, end up betraying him.

It could be the society within the wizarding world that frowns upon same - sex relationships. Even though Ron's feelings are unrequited, the general attitude of the wizarding community might put pressure on Harry, and in a way, act as an antagonist. Charlie would then be rescuing Harry from this external pressure as well as Ron's unwanted romance.

Maybe a new dark wizard or witch emerges. This character is extremely powerful and manipulative. They target Ron and Hermione because they are Harry's closest friends. By turning them against Harry, this antagonist hopes to isolate Harry and make him easier to defeat. The new antagonist could have some unique magical abilities that allow them to control the minds of others or create very convincing false scenarios.

It could be a dark wizard who has a long - standing vendetta against Ron's family. This wizard might see turning Ron undead as a way to get revenge on the Weasleys. He could be lurking in the shadows, trying to make Ron's undead state even worse by casting more dark spells on him.

Another possibility is Snape. Snape might be suspicious of Ron's transformation and think it's some sort of dark magic at play. He could constantly be on Ron's case, trying to figure out what happened and making her life difficult in potions class and around the school in general. He might also suspect that Ron is up to something that could disrupt the order at Hogwarts.

The main antagonist could be a jealous classmate. This classmate is envious of Ron's friendship with Harry and Hermione. So, they find a way to use dark magic to turn Ron into a fiend, hoping to drive a wedge between them. However, as the story progresses, they realize the consequences of their actions are far more serious than they thought.

One possible plot could be that they have a major disagreement over a Quidditch match. Maybe Ron blames Harry for losing the match because Harry made a risky move that didn't pay off. This causes a rift between them, and they start to see each other as rivals rather than friends. They compete in everything from academics to getting the attention of a certain teacher.