Harry may show greater power in his connection to the magical world around him. He has always had a special bond with Hogwarts. In the fanfiction, this bond could be enhanced. So, when Voldemort tries to attack the school, Harry is able to draw on the magic of Hogwarts itself. He can use the ancient magic stored within the castle walls to create powerful shields and offensive spells that are far more potent than anything Voldemort can muster.
Loki shows his greater power through his illusions. He can make Thanos believe things that aren't true, like creating false armies or making Thanos think he has lost the Infinity Stones. This mental manipulation is a form of power that can be more effective than Thanos' physical strength.
One reason could be his pure heart. Harry's pure intentions and lack of desire for power for power's sake gives him an edge. His magic is not corrupted like Voldemort's. It flows more freely and is more in tune with the natural order of magic. So, when he casts spells, they are more effective.
Well, in many such fanfictions, Harry might achieve power through intense magical training. He could study ancient spells and magic that others don't dare to touch. Maybe he discovers a hidden magical heritage within himself that gives him an edge. For example, he could find out that he has some connection to a powerful magical family from long ago that had unique powers.
Well, in the fanfiction, Percy could have greater power in terms of strategic thinking related to his powers. For instance, he can use water to create diversions, like huge waves to distract enemies while he maneuvers into a better position. And his power might not be as draining as Jason's, enabling him to keep using his abilities for longer periods in a fight. So, these aspects can show that Percy is more powerful.
Well, he may show his power by having an innate ability to understand and manipulate magic in ways that are beyond normal wizards. For example, he could be able to sense magic in objects or people in a much more detailed way, allowing him to uncover hidden secrets or foresee danger. He might also have a unique connection to some ancient and powerful magic source that gives him an edge in any magical encounter.
It completely flips the power structure. Normally, Dumbledore is seen as one of the most powerful wizards in the original series. But in this fanfiction, Harry being more powerful means that the traditional hierarchy is disrupted. For example, battles and challenges that Dumbledore would usually handle might now be Harry's domain.
Maybe Harry uses some powerful and unexpected spells. For example, he could combine the Patronus Charm with a blasting spell. The Patronus might distract Voldemort while the blasting spell hits him hard.
In this fanfiction, Voldemort's character is explored in a way that challenges our traditional view of him. His seeing Harry abused might make him reevaluate his relationship with Harry. He may start to see Harry not just as the Boy Who Lived who he wants to defeat, but as a person who has suffered, much like he might have in his own way. Harry, on the other hand, is stripped of some of his heroic facade. His abuse makes him more relatable in a sense. We can see his pain and how it affects his actions and decisions, and also how he reacts to Voldemort's new - found interest in his situation.
It might start with Voldemort's initial curiosity. He realizes Harry is more than just a threat. So he begins to observe Harry closely. As time goes by, Voldemort may start to feel a strange sense of connection, like he's the only one who truly understands Harry's power.
Dudley often shows his jealousy through mean actions. He might bully Harry more in fanfiction, like taking his things or pushing him around. It's his way of trying to assert dominance since he feels inferior to Harry in other aspects, especially when it comes to Harry's magical world.