As a young Tom Riddle pointed out to Professor Slughorn, seven is the most powerful number. Once one begins looking for this special number in the Harry Potter franchise, it quickly becomes apparent that J.K. Rowling was planting the number seven anywhere and everywhere; from seven books to seven Quidditch players making up a team, and Voldemort's plan to split his soul seven ways.
Throughout the Harry Potter world, there are also plenty of characters who embody the seven deadly sins, these being gluttony, envy, sloth, wrath, greed, lust, and pride. While some of the characters were able to overcome their own particular vice, others suffered terrible fates because of theirs.
7 Gluttony: Dudley Dursley
From minute one, both book and movie fans are introduced to the gluttony of Harry Potter's cousin Dudley Dursley. There is barely a moment when the boy is not eating or asking for more food; pleas that are usually obliged by his overindulgent mother. By the third book, Dudley's problem had grown so large, he complained about the distance between the TV and the kitchen, a problem that was solved not by a diet, but by a TV being installed in the kitchen.
The year after, his gluttony and obesity reached breaking point, and he was finally forced onto a diet by his school nurse. Although he hated this at first, throwing countless tantrums and rebelling when his parents couldn't see, Dudley was eventually able to turn his weight and new, albeit forced, discipline to boxing.
6 Envy: Petunia Dursley
When a young Petunia found out that her younger sister Lily had special powers and was set to attend Hogwarts School of Witchcraft and Wizardry she was naturally jealous. After writing a letter to headmaster Albus Dumbledore and politely being turned down in her request to also study at Hogwarts, Petunia's envy reached new and unhealthy levels which went far beyond a normal sibling rivalry.
Over the years, Petunia began to disguise her jealousy as hatred and opted to ignore the magical world completely, severing ties with her "freak" sister. This unresolved envy eventually led to the neglect of her orphaned nephew Harry Potter, who, just like his mother, was guilty of nothing other than being born different.
5 Sloth: Gilderoy Lockhart
Gilderoy Lockhart might not appear to embody the sin of sloth or laziness with his immaculate hair and fancy lilac robes, but that is all part of the image he created. Towards the end of Harry Potter and the Chamber of Secrets, it is revealed that Professor Lockhart is not actually a successful defender of the people against the Dark Arts, but a massive fraud.
By launching a book career based on the deeds of genuine heroes, Lockhart was able to rise to the top of wizarding celebrity culture and presumably make quite a fortune in the process. As he said himself, he did have a certain knack for memory charms, however, instead of using his skills for good, he took the easy option and hoodwinked witches and wizards out of their stories before removing their memories. At the end of both the movie and the book, he is given a chance to finally prove himself and save a child. Instead, his slothfulness and cowardice result in him losing his mind after his own memory spell backfired.
4 Wrath: Harry Potter
Harry Potter was a boy of many virtues, humility, loyalty, and love, all of which and more were crucial in overcoming the Dark Lord. However, Harry was also known for his outbursts of anger, especially in his later years at Hogwarts. Throughout the fifth book, he is constantly unloading his wrath on friends Ron and Hermione, who understood his distress but eventually had to confront him. On another occasion, Harry even wrecks Dumbledore's office, a moment of grief not shown on the big screen.
Harry was not a cruel person by any means and had the difference pointed out to him by Bellatrix Lestrange as he tried to inflict the Cruciatus Curse on her as revenge for Sirius. Harry's wrath can be expected from one who went through so much and with the part of Voldemort within him expelled, it is likely that most of Harry's anger issues went away in his later years.
3 Greed: Mundungus Fletcher
Greed is the overt desire for material wealth and can often drive a person to bypass both legal and moral codes in order to gain. A reluctant member of the Order of the Phoenix, Mundungus Fletcher was known for a greedy eye and disregard for the law. Constantly throughout the latter part of the series, he would engage in dodgy deals and take advantage of any situation for profit. With a complete lack of empathy, Mundungus was even caught selling the Black family's heirlooms after Sirius' death.
Mundungus' greed was so problematic that in Harry Potter and the Order of the Phoenix, he abandoned his post and responsibility of watching over Harry for an opportunity involving stolen cauldrons. This ended up being an oversight that could very easily have resulted in Harry losing his soul to a Dementor's Kiss, or worse still, being expelled from Hogwarts.
2 Lust: Merope Gaunt (Riddle)
There aren't many examples of lust in the Harry Potter franchise. After all, the beginning of the series is primarily for children. Nevertheless, there are implied examples of lust and most certainly cases of unbridled desire for love that take advantage of magic. Merope Gaunt was a descendant of Salazar Slytherin who grew up in poverty with her magical prowess suppressed by an abusive father.
However, she would go on to abuse power herself when handsome muggle Tom Riddle refused her advances. Her lust drove her to commit a great crime, wherein she used magic, presumably the Imperius Curse or a love potion, to make Riddle fall in love with her against his own will. When Riddle escaped the entrapment, Merope was left with naught but guilt, sorrow, and a pregnancy that would end in her death and an unloved orphan who would go on to become Lord Voldemort.
1 Pride: Lord Voldemort
Lord Voldemort possessed many aspects of the seven deadly sins, and many other flaws besides. However, it was his innate and misguided pride that led him down the path of self-destruction. Tom Riddle knew pride from a young age, a sense of being better than others that was heightened by the confirmation of his wizarding nature. Voldemort held magical ability in such high esteem that he could not fathom the idea of his mother being a witch, for if she could use magic, how could she die?
In later years Lord Voldemort was known to brag about having gone further than any wizard before him, even his adoption of the title "Lord" and anger upon being called by his Muggle name, shows immense vanity. By becoming in his own eyes the greatest wizard to ever live and seemingly conquering the weakness of death, Voldemort was blinded by pride and thus unable to even see his own shortcomings, let alone address them. The complete disregard for anything other than power and supreme magical ability eventually led to his death.