Harry Potter and the Prisoner of Azkaban attacked by a big black dog, which Harry has seen several times before. The dog drags Ron through a tunnel under the Whomping Willow into the Shrieking Shack. Harry and Hermione follow, and there is a brief standoff when they find Ron with Sirius Black, who has transformed from the dog. Lupin enters, and they explain the situation to Harry and his friends: Lupin is a werewolf, which led to his friends James Potter, Sirius Black, and Peter Pettigrew becoming animagi. Lupin explains that Scabbers is Pettigrew in his animal form; he has been hiding from Black, whom he had
Harry Potter Voldemort's followers (nicknamed Death Eaters) at the Ministry of Magic. Although the timely arrival of members of the Order of the Phoenix saves the teenagers' lives, Sirius Black is killed in the conflict. In the sixth book, "Harry Potter and the Half-Blood Prince", Voldemort begins waging open warfare. Harry and his friends are relatively protected from that danger at Hogwarts. They are subject to all the difficulties of adolescence – Harry eventually begins dating Ginny, Ron establishes a strong infatuation with fellow Hogwarts student Lavender Brown, and Hermione starts to develop romantic feelings towards Ron. Near the beginning of the