"I could do you for afters, Dumbledore..."
- Greyback to Professor Dumbledore atop the tower, implying that he's already eaten someone shortly before
Fenrir Greyback is a supporting antagonist in Harry Potter and the Half Blood Prince. He is a sadistic Werewolf who serves as a high-ranking member of the Death Eaters and had sought to lead every Werewolf in a violent and wild life-style - naturally for an repulsive bloodthirsty mass-murderer.
He was played by the late Dave Legeno.
Greyback was in the First Wizarding War and was a ruthless Werewolf who took no remorse in killing. He was either infected as a youth or during his childhood. Unlike other Werewolves, he showed a delight in transforming, going as far as to express lupine tendencies and aggression in his human form.
During the First Wizarding War, he was convicted of killing Muggle children, and bought before the Ministry for a trail. However, Greyback was such a good actor he passed himself off as a homeless Muggle man who claimed to be astonished at being in front of a congregation of wizards and disgusted by child killings. Given Greyback's stale smell and scruffy appearance, the court almost believed his homeless story, until Lyall Lupin, Remus Lupin's father, who was a court martial at the time, noticed the signs of Lycanthrophy in Greyback's face. He noted the pallour that set in during full Moon (coincidentally, it was going to be a full Moon the next day) and Lyall said how Werewolves were brutal monsters who should all be executed. Lyall was heard by Greyback, who was enraged, and by the other ministers, who said Lyall should be rounding up centaurs instead. However, Lyall demonstrated Greyback's lycanthrophy to the whole court, and Greyback yelled he would make Lyall pay as he was thrown back outside.
A few days later, Greyback found the Lupin home, broke into young Remus' room, and bit him as he slept. He thus paid Lyall back and gave Lyall a Werewolf with which to live with. Lyall tried to find a cure for Remus but none worked. He eventually learned to put up with the affliction and stress of the infection his son had.
During the Second Wizarding War
He appears in the sixth and the seventh Harry Potter book and their respective movie adaptations. During Draco Malfoy's sixth year, he appeared at Hogwarts thanks to the Vanishing Cabinet in the Room of Requirement. He was with the other Death-Eaters on the Astronomy Tower when Albus Dumbledore was murdered by Severus Snape. He also also set the Burrow on fire with Bellatrix Lestrange.
He, along Scabior, became furious when the Malfoys tried to hand the trio to Voldemort like if they would have made the work, but he decided to remain in silence for his good. He was later chased away out of the Manor by Bellatrix, but Bellatrix committed a great error when she did so, because without Greyback, the trio were able to escape with Dobby from the Death Eaters, albeit Dobby was fatally stabbed. Thus, Greyback saved from being punished by his master when he arrived.
Following Harry Potter and his friend's infiltration in Hogwarts, Greyback came along the other Death Eaters and Werewolfs to participate in what became the Second Battle of Hogwarts. When student Lavender Brown fell from a balcony, Greyback attacked her, fatally injuring Brown. Hermione Granger, however, arrived with Harry and Ron Weasley. Upon seeing that Greyback did, Granger blasted him and Greyback fell out from a window of the Viaduct Courtyard. It's completely unknown if Greyback survived the fall or not, but if he survived it, he was most likely arrested and sent to Azkaban following the end of the war.
- WatchMojo.com listed Fenrir Greyback as #8 on their Top 10 "Most Evil Harry Potter Characters" list.