Maybe a dark wizard who has followed Cedric and Harry to Forks and is causing chaos there. He could be trying to use the unique environment of Forks and the powers of the supernatural beings there for his own dark purposes.
It could be a powerful vampire who doesn't like the interference of Cedric and Harry in Forks. This vampire might see them as a threat to the secrecy of the vampire community in Forks.
Harry is the protagonist from the wizarding world, known for his bravery and his fight against Voldemort. Cedric, on the other hand, was a popular and kind - hearted student at Hogwarts. In this fanfiction, they are the central figures as they are the ones who will experience the new environment of Forks and interact with whatever they find there.
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.
One possible plot could be that Cedric and Harry are transported to Forks for some mysterious reason. Maybe they discover the existence of vampires and werewolves there. They could get involved in the local supernatural drama while also trying to find a way back home.
It could be Voldemort. Even though he's from the Harry Potter universe, if he finds out that Harry is hiding in Forks, he could send his Death Eaters there. This would not only put Harry in danger but also the Cullens and the people of Forks as the Death Eaters might start causing chaos.
Well, it could be that Harry and Cedric find themselves in Forks for some magical reason. Maybe they are on a mission to protect the town from dark forces that are starting to surface there. They might use their magical skills in a world that is not used to magic, like in Forks which is more of a normal human town in the Twilight universe.
Perhaps a new, powerful demigod - vampire hybrid that Percy has to face. This hybrid could be causing trouble in Forks, and Percy has to stop it before it destroys the delicate balance between the vampires, werewolves and humans there.
They might meet Bella and Edward from the 'Twilight' series. It would be really interesting to see how Harry and Edward interact, considering they are both kind of outsiders in their own ways. Luna could become friends with Bella, sharing their different views on the world.
The main antagonist might be a being from another dimension who is able to manipulate both magic and the Hulk's gamma - irradiated energy. This being wants to use the chaos caused by the meeting of Harry and the Hulk to open a portal to let in more of his kind to take over all the universes. He sets traps for Harry and the Hulk and constantly tries to keep them from working together to stop him.
Perhaps a rogue Overwatch agent who has turned against the organization. When Harry arrives, this agent sees an opportunity. He believes that by using Harry's magic, he can take over Overwatch and rule the world. So he tries to manipulate Harry and turn him against Tracer and the rest of the good - hearted Overwatch members.
The main characters are Cedric and Harry. Cedric, a popular and talented student at Hogwarts, decides to take Harry under his wing. Harry, who has had a tough life so far, now has to adjust to living with Cedric. There could also be minor characters that are important for the story, such as Cedric's professors who might notice the change in Cedric's behavior due to his new responsibility of taking care of Harry, or Harry's enemies who might be more cautious now that Harry is under Cedric's protection.