Maybe Harry uses his connections. He has friends like Hermione who is very intelligent and could come up with strategies. Ron, with his family's influence in the wizarding world, could also help. Together, they could figure out a way to get Harry into a position of power within the Wizengamot. It could start with him solving some internal problems within the Wizengamot, showing his competence and thus gradually taking control.
Well, in some fanfictions, Harry might gain control over the Wizengamot through his heroic deeds. For example, if he saves the wizarding world from a great threat again, the public support could be so strong that he can influence the Wizengamot's decisions. He could also use his knowledge of magic, especially some ancient or powerful magic that gives him an edge in the political arena of the wizarding world.
He might use powerful magic or make bold statements to intimidate them.
He might face political intrigue. There are likely those in the Wizengamot who oppose him due to his past actions and his association with Dumbledore. Also, he has to deal with the complex and often archaic laws and traditions of the wizarding world which could be a huge obstacle.
The Wizengamot can also be a place for character development. A character like Ginny might have to plead a case in front of them, and through this experience, she could grow in confidence and political savvy. It's a great way to explore different aspects of a character that might not be shown in the original books. Well, think about it. Ginny is usually shown as a brave Quidditch player, but in this context, she becomes a political figure of sorts. It gives her a new dimension.
In the fanfiction, the Potter ring could act as a sort of key to unlocking hidden knowledge about the wizengamot's history and secrets. As Harry uncovers these secrets, he could use them to his advantage in the wizengamot. He could expose corrupt members or present solutions to long - standing problems, thus elevating his standing within the magical governing body.
He becomes more politically aware. Through his experiences in the Wizengamot, he starts to understand the power dynamics and the behind - the - scenes workings of the wizarding world. His character evolves from just a hero on the battlefield to a political figure.
In some fanfictions, it could be through intense magical training and study. Maybe he discovers an ancient spell or a hidden magical technique that allows him to assert control over the dangerous Fiendfire.
Well, it might be related to his connection with the Dark Lord. Since Voldemort was able to control the basilisk before, and Harry has a unique connection to Voldemort through the scar. This connection could be manipulated in some way in the fanfiction, allowing Harry to take over the control of the basilisk from Voldemort.
In some fanfictions, Harry might gain the ability to control Fiendfyre through intense magical training. He could be mentored by a powerful wizard who teaches him the dark arts in a controlled way, allowing him to master Fiendfyre. Another possibility is that he inherits some ancient magic that gives him this power. For example, if he discovers a long - lost family heirloom that has the magic to control such dangerous spells.
In this fanfiction, Harry might also form alliances within the Wizengamot. He could team up with some of the more progressive members to counter the conservative forces. His skills as a wizard and his leadership qualities from his time at Hogwarts could come in handy in the political arena of the Wizengamot. He could even start initiatives to improve the relations between the wizarding world and other magical creatures, which would be a significant step forward in the world of Harry Potter fanfiction.
Hermione would likely be one of his allies. She's intelligent and has a strong sense of justice, always having been interested in the rights and wrongs of the wizarding laws. She could provide Harry with valuable research and advice.