One common opponent could be other dark wizards. These wizards might also be skilled in dragon dueling and use their dragons to spread chaos. They would see Harry as a threat and try to defeat him in duels.
There might also be rival students from other magical schools. In the world of fanfiction, other schools could have their own dragon dueling traditions. These students would come to Hogwarts to challenge Harry and prove their superiority in dragon dueling.
Voldemort is a common one. In many fanfictions, their duels are epic battles of good vs evil, with Harry using his duelist skills to outwit Voldemort.
One great fanfiction could be where Harry discovers a hidden talent for dragon dueling. Maybe he stumbles upon an ancient spellbook that teaches him unique dragon - dueling techniques. He then uses these skills in a secret underground dueling arena, facing off against powerful opponents and their fearsome dragons.
In many Harry Potter dragon duelist fanfictions, Hagrid is a beloved character. His love for all magical creatures, especially dragons, could lead to some interesting storylines where he either helps train dragon duelists or gets involved in some way. Luna Lovegood is another character that often shows up. Her unique perspective and magical abilities could make her an unexpected but powerful dragon duelist. And then there's Sirius Black, whose wild and rebellious nature could be well - suited to the high - stakes and dangerous world of dragon dueling.
Well, there are many. For example, a plotline might center around a dragon duelist who is wrongly accused of using illegal spells during a duel. They then have to clear their name while also preparing for an important upcoming duel. Another could be a story where a young girl discovers she has a special power that allows her to communicate with dragons during duels, giving her an edge. This power, however, attracts the wrong kind of attention from some dark wizards. Also, a plot could be about a dragon - dueling club in Hogwarts that is on the verge of being shut down due to some mysterious accidents during duels, and the members have to find out what's really going on to save their club.
Hermione would most likely help. She's always been there for Harry, and with her vast knowledge from books, she could offer a great deal of advice on how to take care of the dragon egg. Ron might also be involved. Despite his initial fear of things, he has a brave heart and would probably stand by Harry's side.
Voldemort could be one of his main opponents, even in the game world. Voldemort might try to use dark magic within the game to defeat Harry. Another could be Draco Malfoy. Draco would be jealous of Harry's success in the game and try to undermine him at every turn, using his family's influence within the game's magical society.
One challenge would be the goblins. They are very protective of Gringotts and would not easily give up control. They have their own laws and traditions regarding ownership. Harry would have to deal with their resistance and find a way to convince them or negotiate with them.
It could be some Death Eaters who are causing chaos at the World Cup. They might be trying to disrupt the event and target Harry.
Obviously, baby Harry Potter himself is a central character. Then there's Dumbledore, who often plays a crucial role in these fanfictions, whether it's making decisions about baby Harry's future or protecting him. Hagrid also frequently appears as he has a special connection to Harry. The Dursleys are common too, as their treatment of baby Harry can be explored in different ways in fanfictions.
In addition to the famous ones like Nearly Headless Nick and Moaning Myrtle, there could be the ghosts of former Hogwarts professors. These ghosts could offer Harry unique insights into the history of Hogwarts and the magical arts. For example, the ghost of an old Potions master might give Harry some rare potion - making tips or warn him about a new danger lurking in the castle. Another possibility is the ghosts of students who died in some sort of magical accident long ago. They might be seeking Harry's help to resolve some unfinished business or find peace.