Muggles' Guide to Harry Potter/Characters/Fenrir Greyback

Overview
Fenrir Greyback is the most savage, cruel werewolf in existence. He considers it his duty in life to bite as many people as possible, so he might one day have enough werewolf followers to rebel against the wizarding world. Lord Voldemort frequently uses him as an effective threat to force people into doing his bidding. He is described as "a big, rangy man with matted grey hair and whiskers", smelling powerfully of dirt and sweat, and having long, yellow fingernails and pointed teeth.

Half-Blood Prince
Draco Malfoy threatens Borgin, at Borgin and Burkes, with Fenrir if Borgin does not assist him in repairing something. We don't learn what the something is or how it got broken at this point.

At Christmas, it is revealed that it was Fenrir Greyback who bit Lupin as a boy, because Lupin's father had offended him. Lupin tells us that Fenrir will deliberately place himself near human dwelling places on full moon nights, thus making it near certain that in his animal state he will at least infect others.

In the ending of this book, Fenrir Greyback is with the Death Eaters who come to Hogwarts to kill Dumbledore; he is one of the four Death Eaters who follow Draco to the top of the Astronomy tower. He attacks and bites Bill Weasley, but because it is not during the full moon and Greyback was not in his wolf form, the only lasting effects on Bill are scars and a newly developed taste for very rare steaks.

Deathly Hallows
Fenrir Greyback is one of the gang of Snatchers who capture Harry, Ron, and Hermione after Harry incautiously speaks Lord Voldemort's name. They are initially fooled by Harry's appearance – Hermione has hit him with a spell that made his face swell up – they eventually determine that this is the Harry Potter for which there is a large reward offered, and decide to take him to Malfoy Manor. While Greyback is evidently the leader of the group, it is revealed that he does not possess the Dark Mark which will grant him unfettered access to the Manor; he is not a full Death Eater. Once in Malfoy Manor, Bellatrix Lestrange offers Hermione to him as a victim; evidently he has cultivated a taste for human flesh even in his non-transformed state. Once Bellatrix sees the sword of Gryffindor, however, she retracts the offer; in order to find out how the sword got out of her vault at Gringott's, she has to interrogate one of the Trio, and she selects Hermione. Once she has the story from Hermione, corroborated by Griphook, she offers Hermione to Fenrir once more. As they escape with Dobby's help, Harry seizes the three wands Draco Malfoy is holding and Stuns him with all three wands at once, leaving him unconscious behind a chair.

In the Battle of Hogwarts, Greyback is seen to attack Lavender Brown in the Entrance Hall. He is stopped by a well-placed jinx from Hermione, from under the Invisibility Cloak, and is then knocked out by a crystal ball thrown by Professor Trelawney. After the events in the Forbidden Forest, he rejoins the battle, but is brought down by Ron and Neville Longbottom.

Strengths
Greyback is shown as a well-built man and is mentally and physically strong. His sense of smell is at a high standard and he can also use a wand to cast spells.

Weaknesses
Though it is arguable whether this could be called a weakness, he has been said to get 'carried away' while attacking, meaning that he goes into an almost unstoppable frenzy until his victim is dead.

Relationships with Other Characters
Greyback has acted violently towards a number of characters, all of whom have been badly damaged by him. He deliberately bit and infected Remus Lupin, which turned him into a werewolf, because Lupin's father insulted him. He also bites and rips at Bill Weasley's face, in his human form, which leaves Bill scarred for life and slightly alters his personality. In the final battle, he savages and possibly even kills Lavender Brown.

Draco Malfoy claims him as a family friend, though apparently only in order to put pressure on Borgin to do something Draco wants done.

Greyback works in co-operation with other followers of Voldemort, such as his fellow Death Eaters and the gang of Snatchers that abduct the Trio, of which he is a member.

Analysis
There is significant debate as to whether Greyback was in his Werewolf shape or not when Lavender was attacked; much of the debate appears on the talk page for that chapter. One major factor arguing against his being Transformed is the author's habit of never naming characters Harry has not been introduced to, and he has never seen Greyback transformed. The immediate identification of Greyback would imply strongly that Greyback is in his human shape. Against this, there is the description of Greyback as a "grey blur", and the fact that nothing in the text rules out Fenrir (and Lupin) being transformed.