Inspired by this question, I'm wondering if there are any instances of characters turning from good to evil in the Harry Potter universe.

There are a few people who turn from bad to good (such as Snape, Karkaroff, Regulus Black etc.), but I can't think of any instances of going in the other direction.

I'm not looking for a complete turnaround as in the linked question, as I doubt there are many instances of a 180 flip (although bonus points if there are), but preferably an example of someone who entirely went from good to evil without being under the effects of the Imperius curse.

For example were there any members of the Order of the Phoenix who defected, or maybe students who were part of Dumbledore's Army who ended up siding with Voldemort (i.e. people who actively worked against Voldemort or other evil forces, and ended up joining them or becoming evil themselves).

A good example would be Peter Pettigrew, however even though he was part of the Order it is never really stated in the books that he was ever "good", more that he just followed his friends, and ended up betraying them out of fear as opposed to evil. I'm thinking more of a Lupin or Kingsley type character who ended up becoming bad.

Sirius would have been a prime example, if the events that everyone believed had transpired at the beginning of Prisoner of Azkaban had been true (i.e. being an upstanding Order member, then becoming Voldemort's supporter and betraying Harry's parents).

  • 25
    luna's father Xenophilius Lovegood? He did not join Voldy, but betray Harry.
    – j4rey
    Commented Mar 31, 2016 at 10:13
  • 11
    Peter "Wormtail" Pettigrew
    – Möoz
    Commented Mar 31, 2016 at 10:36
  • 21
    Does anyone really start evil? I mean, even Voldemort was probably fine when he was a baby... Commented Mar 31, 2016 at 13:14
  • 7
    Mundungus ? He went from member of the Order to completely chaotic (rather than evil) but still.
    – Pwassonne
    Commented Mar 31, 2016 at 14:15
  • 6
    Umbridge went from bad to worse
    – Inazuma
    Commented Apr 2, 2016 at 11:28

8 Answers 8


You have a lot of good examples here, but I'll add one: Professor Quirrell.

A foolish young man I was then, full of ridiculous ideas about good and evil. My master showed me how wrong I was. There is no good and evil... there is only power, and those too weak to understand it...

More so than the other answers you're getting of people who switched sides out of cowardice (like Pettigrew), Quirrell seems to have gone from a good person who taught Muggle Studies and Defense Against the Dark Arts to someone who fully embraced Voldemort's ideology.

  • 1
    How much of that was Voldemort sharing his skull and constantly whispering in his ear? I'm sure my personally would alter radically if that were to happen to me.
    – Xantec
    Commented Mar 31, 2016 at 19:32
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    @Xantec He did develop his interest in the Dark Arts before he ever met Voldemort, and he was well on his way to becoming a nasty piece of work by then. But his time with Voldy definitely sent him over the edge. His Pottermore article describes it in a bit more detail. Commented Apr 1, 2016 at 1:26
  • 3
    Then I'll have to include Ginny as well, as a mild case of Quirrell-itis.
    – cst1992
    Commented Apr 1, 2016 at 5:22

If we're willing to accept going from good to doing bad things as being partially evil, then there's an obvious answer no one's mentioned: Harry Potter.

Harry does a number of morally questionable things in Deathly Hallows. Many of them can be written off as desperate times calling for desperate measures, such as Imperiusing Gringotts staff. However, he also chooses to Cruciatus Amycus Carrow--not because of situational necessity, but in retaliation for his disrespect of Professor McGonagall. There are no exigent circumstances requiring this act. Harry is merely angry and wants to cause pain to someone he considers a justified target.

And we know--from Bellatrix Lestrange's words in Order of the Phoenix--that this simply wouldn't work, absent the actual desire to cause pain for its own sake:

"You need to mean them, Potter. You need to really want to cause pain — to enjoy it"

I think it's pretty clear that focused sadism directed at someone you've never even met before counts as an evil step. Sure, Carrow deserves punishment, he's done horrible things; but this little moment of extrajudicial torture is very difficult to justify in any civilized framework. This isn't even Jack Bauer torture, looking for information; it's for the sheer evil joy of getting back at someone.

  • 65
    Way to court controversy, mate! Welcome to SFF ;-)
    – Rand al'Thor
    Commented Mar 31, 2016 at 16:47
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    Yes, the way JKR treats those who use Unforgivable curses ... is twisted, just like in RL. Harry weasels out scot-free. Commented Mar 31, 2016 at 17:55
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    I'd argue it is not JKR, but the Ministry. It was not unintentional that "good" characters started using Unforgivable Curses in Deathly Hallows. Lupin even mentioned it "at least Stun if you aren't willing to kill." They avoided Unforgivable Curses before because they were illegal, not because there's anything terrible about killing (or mind-controlling) someone who is trying to kill you. That said, Harry's acting against Amycus was an evil action (but not his whole character).
    – Adamant
    Commented Apr 3, 2016 at 3:34
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    I'd postulate that there's no evidence that JKR thinks Harry's use of the Cruciatus Curse was justified, but that the way it played out kinda made sense. Was anyone really going to turn Harry in for using an Unforgivable Curse on a Death Eater? Was McGonagall going to tell him off for his choice of retaliatory curse, when Amycus had been torturing students all year? Naturally, using the Cruciatus Curse when Stunning spells and so forth are available is wrong. But Harry getting away with it makes sense. The scales don't always balance.
    – Adamant
    Commented Apr 3, 2016 at 3:38
  • 3
    Of course it's evil to want to cause Bellatrix pain!
    – Obsidia
    Commented Apr 20, 2017 at 13:52

As Padfoot says,

The world isn't split into good people and Death Eaters.

So 'joining Voldemort' would be a narrow definition of 'evil'.

Broadening that definition a bit, I could think of some:

  • Petunia Dursley(I get it, she had problems, but if not opposing Vernon and Dudley when they harassed Harry could be considered as a form of evil; we have no reason to believe she didn't say anything when she could have).

  • Grindelwald was another - he wasn't evil to begin with, just mischievous, but he turns evil in the end resulting in that duel and his lifelong incarceration in his own prison.

  • Pettigrew, of course.

  • Snape. Although we assume he was evil -> good, he actually was good -> evil -> good. He is shown to be good friends with Lily in childhood, but is plainly evil in adulthood as has been shown on multiple occasions.

  • 1
    I could think of more - Marietta, Draco, Petunia is a borderline case, even Sirius himself to a mild extent in the events of PoA. But these would be ones who were under pressure from external elements: desperation, circumstances etc. So I didn't include in the main list.
    – cst1992
    Commented Mar 31, 2016 at 11:13
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    Petty and jealous yeah, but not evil.
    – cst1992
    Commented Mar 31, 2016 at 12:28
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    Not sure I’d agree with Snape being ‘good’ even as a kid. Already at the time we first see him, he was rather a spiteful and vicious kid, damaged by his parents’ violent relationship and his own rather traumatic childhood. Lily is the only one he’s ‘good’ around, and he pretty much stays like that. It’s more a case of her bringing out the good in him than him changing from good to bad, as such. Commented Mar 31, 2016 at 12:28
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    Evil has a more striking definition, like Voldemort - he was evil, right from the start. He used to steal stuff, kill animals, and keep away from everyone. Even in school, everything he did was for personal gain. Snape was different - he was a troubled child, but not evil.
    – cst1992
    Commented Mar 31, 2016 at 13:41
  • 2
    I'll disagree with Grindelwald. Paraphrasing here, but even Dumbledore says that he "pretended not to see what he really was" or something. He presented himself as an outgoing, well-intentioned radical, but even then he was a psychopath. Commented Mar 31, 2016 at 16:51

[Note: this answer was written before the bit about Peter was edited into the question; I leave it up because I still think he is the best example.]

The most obvious answer I can think of is Peter Pettigrew.

While he was never really what you might call a thoroughly good person, he was friends with James, Remus, and Sirius for many years while at Hogwarts, and his main character flaw there was apparently his insecurity. He was presumably always a bit of a coward, but he had strong friends and his cowardice didn’t seem to have made him a particularly bad person at this time.

His tendency to seek safety by siding with the ‘biggest boy in class’ and thus ending up in Voldemort’s camp was initially simply motivated by cowardice, but towards the end, during Deathly Hallows especially, he is no longer as much a coward as a truly bad person.

  • Sorry, I was writing already writing my update and didn't see this answer posted! Commented Mar 31, 2016 at 10:48
  • 2
    Also, I'd add to this, from the reader's perspective, we first meet him as this benign, slightly limp and useless, rat Scabbers, for which you might feel anything from mild contempt, through indifference, to mild fondness. But he was the pet of Ron, he bit Goyle, you feel really sorry for him in PoA, you think he's been gobbled by Crookshanks. And then he turns out to be this traitor and one of the central villains to the plot
    – Au101
    Commented Mar 31, 2016 at 10:50
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    Of course, it's debatable if any of the Marauders (sans maybe Lupin) could be considered "good" when they were that age.
    – DavidS
    Commented Mar 31, 2016 at 10:50
  • I'd say he turned "evil" on or before the night he confronted Sirius.
    – cst1992
    Commented Mar 31, 2016 at 11:27

Aragog the spider could be considered. Was once Hagrid's pet / friend who was happy enough to answer some of Harry and friend's questions only to let his children (thousands of spiders) try to eat them.

  • 26
    Hm. 1) Had Aragog actually the authority to stop his offspring from trying? 2) Had he really reason to? This is moving into ethics, and human ethics don't really apply to giant spiders. Carnivores eat animals, and a human is an animal. Who's to say which kind of animal is "OK" to eat and which isn't? Humans eat whales, dogs, and monkeys, too. I don't see "evil" here.
    – DevSolar
    Commented Mar 31, 2016 at 14:56
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    I don't think arachnid ethics necessarily align with human ones. Commented Mar 31, 2016 at 19:17
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    Regardless of whether Aragog’s actions were evil, I’m not sure there’s much reason to believe that he had ever really changed — he may have been just as evil/amoral/whatever when he was smaller and still Hagrid’s pet, only less able to exercise it on a human scale. I always saw Aragog as a bit of a cautionary lesson — showing that Hagrid’s trusting and generous nature, while a great thing most of the time, can also end up putting innocent people in danger, by being unable to acknowledge someone’s/something’s faults and the risks they pose.
    – PLL
    Commented Apr 4, 2016 at 0:35

Gellert Grindelwald

He was maybe not the nicest person ever, but I don't know if he was truly evil when Dumbledore first befriended him.

Dumbledore was somewhat infatuated but I believe he would have known an evil person from a misguided one.

Grindelwald slowly turned more and more evil but as teenagers I would call both of them misguided but neither evil at that point.

  • He did get expelled from Durmstrang before meeting Dumbledore
    – CHEESE
    Commented Apr 4, 2016 at 17:18

This could be a difficult sell: Voldemort. He may have had bad genes, but his backstory shows sponsorship by Dumbledore and it was Riddle's insecurities that turned him into an evil menace. Every issue can be traced back to fear of death and abandonment. You are not born an evil murderer. Circumstances and opportunity must line up to transport from mentally ill to evil. http://harrypotter.wikia.com/wiki/Tom_Riddle

  • IIRC, it was maybe more a matter of increased ability / motivation to perform increasingly evil actions. Riddle could still be evil even if he didn't murder anyone. Commented Apr 3, 2016 at 21:51

In the alternate timeline created by Scorpius and Albus interfering with the second Triwizard Tournament task, Cedric Diggory ends up becoming a Death Eater.

SCORPIUS enters the library and starts desperately to look through books. He finds a history book.

SCORPIUS: How did Cedric become a Death Eater? What have I missed?

Harry Potter and the Cursed Child, Act 3, Scene 4

Cedric is at least a decent guy originally, as we know from him helping Harry out with the "take a bath" tip to help Harry discover the nature of the second task. So this probably counts as a good character becoming evil, at least in that particular alternate reality.

  • 1
    FYI, while it has been stated that Cursed Child is canon, that statement came from the marketing team behind it, not from Rowling. Apparently Rowling even debunked that statement.
    – Egor Hans
    Commented Mar 23, 2021 at 12:51

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