While the argument can be made every moment is important, some events and decisions from the Harry Potter franchise stand out as truly game-changing. Much of what Harry goes through, in fact, is the result of decisions other people made even before he grew up. However, Harry does have some agency he exerts and makes crucial choices of his own. Still, Dumbledore, Snape, and Voldemort are major players in occurrences that changed so much.
Plenty of the series relies on the supporting characters and their pasts to explain plot holes or things that eventually make sense to the rest of the story, revealing how decisions can have a domino effect. Here are some events which truly shape the narrative.
Ariana Dumbledore Dies
Before his younger sister died, Albus Dumbledore was headed down the path of power. Albus and Grindelwald planned on searching for the Deathly Hallows together. But, everything changed when Ariana was killed.
Her death caused Albus to reevaluate his actions and change direction. He understood the pull of power and, as an adult, holds plenty of it but stayed away from a Ministry position. Instead, Dumbledore took to becoming a professor and later Headmaster of Hogwarts.
Snape Tells Voldemort The Prophecy
Had Snape not done this, there was a chance that James and Lily Potter could have lived. Snape informed Voldemort that a prophecy was made suggesting the Chosen One destined to defeat Voldemort. However, Snape realized too late that Voldemort connected the prophecy to the Potter family, putting Lily's life in danger.
Snape changed sides when Voldemort planned to kill Lilly. Snape's decision to reveal the prophecy made Harry an orphan and was the beginning of Snape becoming a double agent, working secretly for Dumbledore.
Pettigrew Becomes The Potter's Secret Keeper
Sirius Black had originally been James and Lily's secret keeper. After figuring that he would be too obvious of choice, Sirius decided to change it to Peter Pettigrew. This would be one of the worst decisions Sirius ever made.
Unbeknown to the group, Pettigrew would betray them to Voldemort later. Peter gave Voldemort the address he needed to get into the Potter's home and was the reason Harry's parents died. Pettigrew was even the reason Sirius ended up in Azkaban for twelve years.
Using Harry's Blood For Voldemort's Ressurection
Lily's love had protected Harry his entire life. By blood protection, Voldemort could never touch Harry, or Voldemort would burn. It was one of Harry's greatest protections against Voldemort's physical assaults, and Pettigrew strips Harry of that during Voldemort's resurrection.
With Harry's blood in Voldemort's system, Voldemort can touch Harry. Using Harry's blood did allow Voldemort that much, but it didn't make it easier to kill Harry.
Voldemort's Horcruxes
Scared of death, Voldemort created a way to avoid it. Horcruxes would ensure Voldemort's survival even if he were killed. By splitting his soul and hiding it in objects, the Dark Lord got to return and resurrect, allowing him to continue his plan to take over the wizarding world.
Unknown to him, though, Voldemort had accidentally turned Harry into a Horcrux, binding them for as long as they both live. With Harry as a Horcrux, he could look into Voldemort's mind, know his emotions, and detect if another Horcrux was near.
The Ministry Battle
Unfortunately, Harry's drive to save Sirius ends in tragedy. Believing that Sirius is trapped with Voldemort at the Ministry Of Magic, Harry is determined to save him. His friends join him on the mission, using their defense skills to fight Death Eaters. Sadly for Harry, Sirius was never there, and it was all a trap.
During the Ministry Battle is the first time Harry is introduced to the prophecy. When things are looking bad for the group, the Order of the Phoenix comes to rescue them, but Sirius dies in the process, leaving Harry without another significant parental figure.
Harry Watches Snape's Memories
With the war on pause, Harry gets a chance to watch Snape's memories, finally filling in many blanks. Harry understands the depth of Snape and Lily's friendship and the negative turn it took later.
Harry watched as Snape became a double agent and understood the real reason why Snape killed Dumbledore. Harry even finally learns that to defeat Voldemort, Harry must die to destroy the Horcrux inside him. Years later, Harry named his son Albus Severus Potter as a tribute to Snape.
Snape Insulting Lily
It started with a fight between Snape and the Marauders. However, that would not be the main takeaway from the event. Instead, this moment would lead to Snape calling Lily the worst thing a person could call a Muggleborn.
Afterward, Snape tried to apologize, but he backed himself into a corner when Snape believed he could call other Muggleborns such a vile term but that Lily was somehow different. Snape's actions and language effectively ended their friendship and set them both on new courses.
Frank And Alice Are Tortured
Had this not occurred, Neville could have grown up with his parents. Unfortunately, Frank and Alice Longbottom suffered a terrible fate.
This left Neville to be raised by his grandmother, who often compared Neville to his parents. She gave Neville his father's wand rather than let a wand choose Neville. However, later on, she grew to be proud of Neville for fighting Death Eaters. The story highlights the idea that Neville and Harry's fates, at least, high level, may have become swapped very easily, revealing how critical certain choices made were.
Ron And Hermione Become Harry's Best Friends
Harry probably wouldn't have survived until the end of the series without his best friends. Harry and Ron connected immediately on the Hogwarts Express. While they didn't get along with Hermione initially, she became an essential part of the trio after defeating the Troll.
Through the years, Harry relies on Ron and Hermione to help him get through each year of school, and even more so during the Horcrux hunt. Hermione's brilliance saved Harry's life numerous times, and Ron, while he did have his worse moments, could be very loyal. The moments these friendships become cemented really did change everything for everyone involved.