Another possible rival could be a new character, perhaps a transfer student from a different wizarding school. This student could have unique magical abilities that Harry has never encountered before. They might be very confident and arrogant, seeing Harry as the main obstacle to their victory in the competition.
One idea could be that Harry wants to compete in a magical tournament within the wizarding world. He could be competing against other well - known characters like Draco or Cedric. The tasks in the tournament could range from complex spell - casting challenges to finding hidden magical artifacts.
Some powerful dark wizards might also be his rivals. They could see the competition as a chance to get their hands on something valuable in Gringotts, like a dark magic artifact, and would stop at nothing to win, including getting rid of Harry.
Sasuke could be a major rival. Even if Naruto is a child genius, Sasuke's natural talent and his drive for revenge could put him in direct competition with Naruto. They might constantly try to outdo each other in training and in battles.
In a Harry Potter Dueling Champion fanfic, Draco Malfoy could be a potential rival. He has a strong sense of pride and is always eager to prove himself. His family's pure - blood heritage gives him access to some powerful magic and knowledge. Another could be Hermione Granger. She is extremely intelligent and has a vast knowledge of spells. Her thirst for knowledge and competitiveness would make her a formidable opponent in a dueling championship. And then there's Viktor Krum. He is already a well - known and skilled wizard from Durmstrang, with his own unique style of magic that could pose a serious challenge.
There could be a rival who is from a wealthy and well - connected fashion family. They have all the resources and connections but lack Harry's raw creativity. So, they view Harry as someone they need to squash to maintain their family's dominance in the fashion world. This rival might use their family's influence to get better show venues or exclusive fabric deals, leaving Harry at a disadvantage.
It could be a jealous wizard who feels that Harry and his sister are getting too much attention in the wizarding world. This wizard might try to undermine their achievements and even put them in danger.
Hermione would be a great supporting character. She could be the one who first notices Harry's interest in becoming a girl and offers her support. She might share her knowledge of magic that could help Harry in his transformation, like spells for changing appearance or potions that can affect one's gender characteristics in a more subtle way. Also, she could provide emotional support, being a good friend and listening to Harry's concerns about how others will react.
Sasuke could be a rival in this fanfiction. Sasuke has always been strong in fire - based jutsu himself. He might see Naruto's claim as the master of fire as a challenge and want to prove his own superiority. Another could be some of the members from other ninja villages who have also mastered powerful fire techniques. For example, a ninja from the Hidden Rock Village who has a unique and powerful fire - based kekkei genkai.
In a football - related fanfiction, it could be Dash Baxter. Dash is always competitive and might see Danny's sudden improvement in the sport as a threat. He could try to expose Danny's secrets to get him off the team.
A self - proclaimed 'collector' of rare pokemon could be a rival. This person has a huge collection of non - shiny but very rare pokemon and sees Ash's shiny pokemon as the ultimate addition to their collection. They would stop at nothing to get their hands on at least one of Ash's shiny pokemon. And of course, there could be other trainers who simply can't stand the fact that Ash has such an amazing ability and they don't.