In some fanfictions, Snape has badass moments when he outsmarts Voldemort. For example, he manages to mislead Voldemort about the location of a crucial magical artifact. He uses his Occlumency skills to his advantage, hiding his true thoughts and intentions while presenting false information in a very clever way. This not only shows his intelligence but also his courage as he risks his life to deceive the Dark Lord.
There could be a moment where Percy stands up to an unjust authority figure in the fanfiction world. He defies them with such confidence and charisma that it makes him seem like a total badass. Or perhaps he dives into a dangerous, unknown realm to save someone, showing his fearless and selfless side which is very badass.
One possible badass moment could be when bella stands up to a powerful alpha wolf. She shows no fear and uses her sharp tongue to put the wolf in its place.
One badass moment could be when Ezra single - handedly takes on a group of stormtroopers in a narrow corridor. Using his lightsaber and the Force to deflect blaster bolts back at them, he cuts through their ranks like a hot knife through butter. Another might be when he uses his Force powers to manipulate a large ship's controls from a distance to prevent it from crashing into a rebel base.
Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.