Draco Malfoy (Harry Potter)
Draco Malfoy serves as Harry Potter's rival throughout the seven-book series. While he starts simply as a spoiled schoolboy prankster who bullies Harry, Draco evolves to be a serious threat throughout the series, culminating in some moments where the reader, and seemingly sometimes Draco himself, can't anticipate his actions.
Rival characters are often far more compelling than the main antagonist of their respective series. They can be fascinating reflections of the protagonist that inspire change and growth more than any other obstacle. Rivals can range from civil, such as Sonic the Hedgehog and Knuckles The Echidna's friendly competition throughout the Sonic the Hedgehog series, to spiteful, like Michael and Fredo Corleone in The Godfather. Harry and Draco fall closer to the latter side of the spectrum, having intense distaste for each other upon meeting early in book one, which only increases as the series goes on. Where Draco has Harry beaten, however, is in his character development. While Harry does not serve as a particularly captivating hero, Draco undergoes a character arc that culminates in a satisfying redemption. He is clearly subject to a lot of intense parental pressure, being bullied himself into following principles and ideals with which he may not agree, and overcomes this through his own willpower. An enormous missed opportunity to have Draco's development come to a climax is shown in an unfortunately deleted scene in Harry Potter and the Deathly Hallows Pt. 2, in which Draco throws Harry his wand just in time for the final duel against Voldemort. While this wasn't in the book, it is the perfect closing to their rivalry, with Draco repaying the life debt he owed Harry at this point. But even without this scene, Harry and Draco will be remembered as one of the most organic and vindictive rivalries ever depicted on page or screen.