Fantastic Beasts: The Secrets of Dumbledore kept its promise by revealing several details about Dumbledore's life and family that fans never knew. Dumbledore's history was partially described at the end of the Harry Potter series when Harry worked to accept that Dumbledore was not perfect and his many mistakes were in part formed by past negative experiences.
This theme that a person's past traumas will often influence their choices is prevalent in the Harry Potter and Fantastic Beasts series. Characters like Harry, Dumbledore, Snape, and even Voldemort are products of their experiences. However, a person's story is ultimately dictated by how they choose to handle those experiences. Every main character of the Harry Potter series goes through terrible things, and while they all didn't manage their pain the same way, they defined themselves by what they did with it.
Luna Lovegood - Losing Her Mother
Luna once revealed to Harry that her mother had died when one of her experiments with magic went wrong. When it happened, Luna had been a young girl, but she still remembered her mother clearly and would never forget her.
Pandora Lovegood was likely just as eccentric as her husband and daughter, but the books hint that she had been a considerably better caregiver than Xenophilius Lovegood. Harry noticed that Luna looked cleaner and more cared for in photographs with her mother, which hints that Luna's parental care greatly declined after Pandora's death. This makes Luna's outlook on life all the more remarkable, as, despite her past pains and her father's cluelessness, she had great compassion and love for anyone around her.
Neville Longbottom - His Parents' Torture
Frank and Alice Longbottom lost their sanity after being tortured by Bellatrix Lestrange when Neville was very young. He confided in Harry that, while he never knew them before, he was proud to have such as parents.
The Longbottoms' legacy had an unintentionally negative effect on Neville's life. Constantly being compared to them shattered his confidence, which only further invited terrible treatment from family, teachers, and students. Ultimately, Neville had to accept himself as he was, instead of trying to be his parents, resulting in him becoming one of the best wizards in the Harry Potter series despite his hardships.
Draco Malfoy - Joining the Death Eaters
After being raised within a family that greatly valued the Dark Arts, Draco considered it a tremendous honor to be accepted into the Death Eaters. He had always considered himself superior to other wizards, let alone Muggles, so Voldemort's mission aligned with his own goals.
However, Draco quickly learned that Voldemort and the Death Eaters were darker than he had ever wanted to go. In punishment for his father's crimes against Voldemort, Draco was forced to torture Voldemort's prisoners on his behalf. In the end, the experience traumatized Draco. He never had the strength to turn against the Dark Lord himself, but after his defeat, he appeared to make some changes for the better.
Rubeus Hagrid - Losing His Father
Despite his enormous size, Hagrid is one of the most caring and gentle characters in the Harry Potter series. But unfortunately, Hagrid went through more misfortune in his early life than he ever came close to deserving.
In his second year at Hogwarts, Hagrid got word that his father had died. Since his giantess mother had left long before, Hagrid was an orphan without a home. However, Dumbledore welcomed Hagrid with open arms, and he began to live full time at the castle. Despite having lost his parents and, of course, the unfortunate events of his expulsion later, Hagrid continued to maintain his kind disposition. He had every reason to resent the wizarding world that barely accepted him, but his good heart never turned dark.
Hermione Granger - Tortured By Bellatrix
Hermione valued knowledge above all else, and it had managed to get her out of trouble several times before. However, in Malfoy Manor, she was brutally tortured by Bellatrix Lestrange, an experience she would likely never be able to forget.
Despite this horror, she kept her wit, and she convincingly lied to Bellatrix about the sword, which was one of Hermione's best decisions in the Harry Potter series. Also, once she had been taken to safety, she wasted no time helping to carry out their next big plan and bring an end to the war. It would have been easy to back out and refuse to help Harry with his task to protect herself from further torment, but Hermione endured.
Ron Weasley - Tortured By The Horcrux
Ron often felt like he was never quite as good as the people around him. Growing up with five older brothers, it was easy for him to doubt his ability to keep up, and becoming best friends with Harry Potter didn't make things any easier.
This made Ron a perfect victim for Slytherin's locket. The Horcrux affected him far more than the others when he wore it. Voldemort's soul fragment planted images and doubts in his head, exacerbating those already buried there. The Horcrux successfully drove Ron away, causing him to feel immediate regret and shame. However, Ron pushed through those feelings, returned, and destroyed the Horcrux that had tortured him.
Severus Snape - Lily's Death
Despite their differences, Snape and Lily were best friends from the ages of 10 to around 16. They both lived in the same Muggle community, so they spent all of their time together at school and during the summer holidays. However, Snape's fascination with dark magic ultimately drove Lily away, and they went on to live separate lives.
Years later, while working for Voldemort, Snape passed on information that resulted in Lily's death. Devastated over what he'd done, Snape switched to Dumbledore's side. While his intentions may have been selfish at first, he eventually began to tip the scales of his moral ambiguity and dedicated his life to bringing Voldemort down.
Lord Voldemort - His Mother's Deception
Long before Lord Voldemort was born, his mother, Merope, fell in love with a handsome Muggle man, Tom Riddle Sr. To win his love, she gave him a love potion, and they got married. However, just before she gave birth to their son, she chose to stop giving Riddle the potion. To her devastation, he left her immediately. With a broken heart, Merope died just after giving birth.
As a result, Voldemort was lovelessly raised in an orphanage. Once he discovered the truth of his past, his hate for Muggles only grew, and he despised his mother's weakness. In the end, Merope's choices ensured that Voldemort would be Harry Potter's villain.
Albus Dumbledore - The Death of His Family
Like Voldemort, Dumbledore's childhood was negatively impacted by Muggles. A group of them had attacked his sister, Ariana, causing her devastating trauma. His father, Percival Dumbledore, attacked the Muggles in revenge and spent the rest of his life in prison.
Dumbledore developed a slight prejudice against Muggles as a result, but he eventually changed his mind when he saw the damage that kind of thinking could do. Ariana died because of his plans to dominate the Muggle world, and fans will likely see how Dumbledore makes amends in the Fantastic Beasts series' next sequel.
Harry Potter - Seeing Others Die For Him
Since Harry was very small, he has had to watch the people he loved die for him. This started, of course, with his parents and continued with Sirius, Dumbledore, Lupin, Fred, and more. While Harry was never really responsible for their deaths, he carried devastating guilt over their loss.
However, the love these people had for Harry ensured that, whether or not he was the "Chosen One," he would do whatever it took to keep anyone else from dying. Watching the sacrifice of others taught Harry what it meant to love someone and want to protect them with everything he had. In the Battle of the Hogwarts, he was willing to die so that Voldemort would be defeated and his friends — and the wizarding world at large — could be safe again.