Can werewolves turn outside of the Full Moon in Harry Potter?

Question

I’m in a Harry Potter Marauder’s-Era role-play and I’m playing Fenrir Greyback. (I’ve also not read the books/seen all the movies). I'm very loosely interpreting a specific point in canon that I’m having some adversarial feedback with my admins regarding the role of werewolves in Harry Potter.

Does it say, explicitly, in the books that werewolves can’t turn outside of the Full Moon?

There isn‘t much on him outside of the two books Half-blood Prince and Deathly Hallows. The common argument would use the excerpt “Fenrir positions himself near children during full moons so he knows he’ll get them” meaning that he can only turn then and nab his victims, but that could easily mean that he wants to be precise in his wolfish endeavours because he can’t control himself at that point.

Getting back to my point: is there conclusive evidence to say that werewolves cannot turn outside of the moon?

Answer 1

‘Before the Wolfsbane Potion was discovered, however, I became a fully fledged monster once a month. It seemed impossible that I would be able to come to Hogwarts. Other parents weren’t likely to want their children exposed to me.' -- Remus Lupin, werewolf

_{Prisoner of Azkaban - page 258 - Bloomsbury - chapter 18, Moony, Wormtail, Padfoot, and Prongs}

There is absolutely no canon information in Harry Potter that suggests that any werewolf can "transcend" the moon cycle and become a werewolf at any or different times. As a former admin of a Harry Potter RPG myself, I would've dinged you for trying to create a Mary Sue. And the assumption that there not being anything that explicitly states a werewolf cannot transform at other times than the full moon as proof that it is possible is flawed logic. The lack of information does not suggest your pet theory is right.

Some may point out that in Half-Blood Prince, Dumbledore notes to Fenrir that Fenrir has developed a taste for human blood outside of his changing into a werewolf at the full moon. This does not suggest that Fenrir becomes a werewolf more than once a month; it merely shows the level of depravity to which he has sunk.

I have to agree with your admin. There simply is no canon evidence to support your theory. I do suggest reading the books -- they're very good! Good luck.

Answer 2

As further evidence - in HBP, Lupin and others comment that Bill - while savaged by Fenrir in Battle of Astronomy Tower - will not turn into a werewolf because Fenrir wasn't transformed.

'But he wasn't bitten at the full moon,' said Ron, who was gazing down into his brother's face as though he could somehow force him to mend just by staring. 'Greyback hadn't transformed, so surely Bill won't be a – a real – ?'

Surely, if Fenrir could transform outside full moon, he WOULD have transformed for that battle. So most likely, he could not.

Answer 3

DVK has already mentioned Fenrir Greyback attacking Bill in Prince, but I believe there's an even more relevant dialog in that book. Quoting Prince chapter 27.

‘Do it,’ said the stranger standing nearest to Harry, a big, rangy man with matted grey hair and whiskers, whose black Death Eater's robes looked uncomfortably tight. He has a voice like none that Harry had ever heard: a rasping bark of a voice. Harry could smell a powerful mixture of dirt, sweat and, unmistakeably, of blood coming from him. His filthy hands had long yellowish nails.

‘Is that you, Fenrir?’ asked Dumbledore.

‘That's right,’ rasped the other. ‘Pleased to see me, Dumbledore?’

‘No, I cannot say that I am …’

Fenrir Greyback grinned, showing pointed teeth. Blood trickled down his chin and he licked his lips slowly, obscenely.

‘But you know how much I like the kids, Dumbledore.’

‘Am I to take it that you are attacking even without the full moon now? This is most unusual … you have developed a taste for human flesh that cannot be satisfied once a month?’

And if Fenrir talking at all and wearing a cloak wasn't enough proof that he is not transformed at that time, the text later talks about Fenrir's fingernails and moving towards Dumbledore “with his hands outstretched”. (Luckily, I add, for if he was transformed there, he might have smelled the invisible Harry.)

Clearly Fenrir wasn't transformed at the time of that attack, so I agree with DVK's conclusion that he at least could not transform.