Creatures
Nagini
Nagini is the large snake who stays with Voldemort. She bites Arthur Weasley in one of Harry’s visions. Harry later learns she is a Horcrux, and Neville Longbottom kills her with the Sword of Gryffindor in the Battle of Hogwarts.
First mention
Harry Potter and the Goblet of FireChapter: The Riddle House
The book opens in the Riddle House, where Voldemort is in hiding with Nagini and Wormtail before the Quidditch World Cup.