Considering how massive their source material is, the Harry Potter movies have done quite a good job of maintaining a balance between staying truthful to the books and remaining within a viable run time. However, some filmmakers' choices regarding what information to leave out from these adaptations are questionable, to say the least.
Expecting the films to cover every single event and piece of lore conveyed by the books would be unreasonable, but there are quite a few characters who were far more important in the books. According to many Harry Potter fans, they should have been given more depth and screen time in the movies, too.
Updated August 7, 2022 by Maciej Grzymkowski: Condensing the thousands of pages of the Harry Potter books into eight two-hour-long movies was one of the main challenges of producing the legendary film saga. Although the movies told Harry's story in a smart, engaging, and cohesive way, they missed out on some of the major details described in detail by J.K. Rowling in the novels.
Going beyond the events of the seven books, there were certain key characters who played a major role in shaping the Wizarding World before Harry's time, but their stories weren't touched upon in the movies.
10 Peeves
Peeves the Poltergeist is a stellar example of a character that was far more important in J.K. Rowling's books than in the movies inspired by them. After all, he didn't even appear in the films! Long-time fans of the series frequently voice their disappointment at Peeves' absence, as he was a valuable addition to Hogwarts' ghost population, and some of his pranks would work perfectly as comedic relief in the later movies.
As it turned out, Peeves was actually supposed to be in the first movie, and there were even some scenes shot with Rik Mayall, a British comedy legend being cast as the mischievous ghost. Unfortunately, they were cut out of the final draft because of time constraints, leading to Peeves never appearing in on-screen adaptations of the Harry Potter novels.
9 Cho Chang
Cho was introduced in the movies in Harry Potter and the Goblet of Fire, the novels actually mention her as piquing Harry's interest in The Prisoner of Azkaban, where the protagonist notices Cho's impressive Quidditch skills as well as her looks, suggesting that he might be developing a bit of a crush on her as early as the third entry in the series.
Furthermore, while she serves a similar role in the films as Harry's first serious romantic interest, the novels go one step further in depicting their relationship. In The Order of Phoenix, for example, there is an entire section describing their date in Hogsmeade, which ultimately goes wrong as painful memories of Cedric Diggory's death prevent the couple from enjoying themselves. The movies also never mention Cho's passion for Quidditch, which was a central part of her character in the books.
8 Kreacher
The house-elf who resided and served on 12 Grimmauld Place was presented in the movies as a bitter, unfriendly character, bound to serve Sirius Black because of his family's lineage, but he exhibited no particular love or loyalty for his master.
Although a lot of the same can be said about Kreacher from the novels, this elf undergoes somewhat of a redemption arc, especially during the Battle of Hogwarts, where he is described as leading an army of house-elves who fought on the side of the Order of the Phoenix against Voldemort and the Death Eaters.
7 Luna Lovegood
While the casting of Evanna Lynch as Luna Lovegood was a perfect match, the Harry Potter movies didn't really do a great job presenting all the layers of Luna's complex personality. In fact, many fans have accused the movies of bringing Luna's role in the overarching plot as the stereotypical "wacko" of the group, without digging deeper into her origin story.
Despite a few scenes meant to evoke some compassion towards Luna, the films largely ignore the many things she did throughout the novels that helped advance the plot and save Harry from trouble. Those who haven't read the books will miss out on key events that involved the eccentric Ravenclaw member, such as her hilarious commentary of Quidditch matches or the fact that she tried to combat The Daily Prophet's propaganda campaign against Harry by using The Quibbler, a magazine owned by her father.
6 Colin Creevey
The young photographer only made an appearance in The Chamber of Secrets, despite being featured in the later books along with his younger brother, Dennis. The pair were part of Dumbledore's Army in The Order of Phoenix. In the final novel, Colin and his brother were expelled from Hogwarts for being muggle-born.
After playing an important role in The Chamber of Secrets, Colin's character was replaced by Nigel Wolpert, one of the rare characters who only appear in the books. He served as a composite replacement for the Creevey brothers, who were thought to take up too much screen time if portrayed in the same way they were in the books.
5 Madam Olympe Maxime
A great example of another romance that could not be fitted into the movies due to screentime limitations, the love story of Hagrid and Madam Olympe Maxime was limited to their brief fling during the Triwizard Tournament in The Goblet of Fire adaptation, as well as a brief cameo at Bill and Fleur's wedding.
However, her involvement in the Harry Potter storyline did not end there, as revealed by Hagrid in The Order of the Phoenix novel. As it turns out, she was actively involved in helping Hogwarts' groundkeeper on his quest to convince the giants to help in the Order's war against Voldemort.
4 Viktor Krum
All the Triwizard Tournament participants from foreign schools were pushed to the side by the filmmakers in The Goblet of Fire movie adaptation. Although Viktor Krum wasn't all that fleshed out in the book, he played a much bigger symbolic role mainly due to the fact that the novels go into more detail when it comes to describing Durmstrang and Beauxbatons.
The Durmstrang Institute, which Krum attended, was famously notorious for not admitting muggle-born students as well as actively teaching the Dark Arts to its students. There was no mention of that in the movie, which really flattens out Viktor's character and the key aspect of his relationship with Hermione, which was overcoming prejudice and going against Durmstrang's bigoted rules.
3 Neville Longbottom
It should come as no surprise that Neville Longbottom is many people's favorite Harry Potter character. After all, he has undergone a tremendous transformation from a clumsy, self-conscious boy into a courageous, loyal fighter who ends up destroying the final horcrux. The movies, however, omit quite a lot of key facts about Neville, his past, and how he was almost just as important as Harry in the overarching story.
The "Chosen One" prophecy in the books states that the person who would ultimately defeat Lord Voldemort would be born to parents who "thrice defied him" at the end of the seventh month. Neville was born the day before Harry, to a pair of aurors who also stood up to the Dark Lord three times. The novels explore the possibility of him becoming the Chosen One and how it was merely due to Voldemort's unwitting decision to target the Potters' newborn son that Neville was spared the burden of that prophecy.
2 Neville's Parents
Just like the extent of their son's role in the film adaptations, most of Neville's parents' story was left out of the Harry Potter movies. The fifth novel has an entire chapter dedicated to Harry and his friends' visit to St. Mungo's Hospital for Magical Maladies where, alongside visiting Arthur Weasley, they also got to see Neville's parents and the extent to which they were incapacitated for life by the Lestranges and Barty Crouch Jr.
It was a powerful moment right in the middle of the fifth novel, which was not only important from the perspective of Neville's character development but also provided readers with some very important backstory of the long-lasting rivalry between the Order of the Phoenix and Voldemort.
1 James And Lily Potter
Harry Potter's parents might have died long before the start of the series, but they were still a major part of the entire story. In fact, it was their absence that shaped Harry into the wizard he became towards the end of the seventh novel. While their past was briefly touched upon in the movies, especially in the context of Snape's grand revelation in The Deathly Hallows, the films have cut out a lot of facts and events from the earlier lives of Harry's parents.
It made a lot of sense, seeing as depicting the lives of young Lily and James Potter could take up enough time for a whole another movie. The brief snippets included in the adaptations did their job in revealing Snape's love for Lily and disdain for James, but many fans were left yearning for more stories of the past to be depicted on the silver screen.