Nagini

"Nagini tells me that the old Muggle caretaker is standing just outside the door. Step aside Wormtail so I can give our guest a proper greeting. Avada Kedavra!"

- Voldemort after Nagini speaks to him in Parseltongue



Nagini is a long, green female serpent belonging to Lord Voldemort. She can be compared to Salazar Slytherin's Basilisk, both of the snakes sharing an important role as a creature loyal to the Dark Lord. Voldemort used Nagini to help him regain strength during the years he had lost his power. With the help of Peter Pettigrew, he milked her venom which helped him stay alive until he could regain a body. Voldemort is able to communicate to Nagini, due to the fact he is a parselmouth, which gives him a lot of command over Nagini. After Voldemort had regained his body, he did not get rid of Nagini. He kept her unusually close to him, which led Albus Dumbledore to believe that Lord Voldemort had turned Nagini into a Horcrux. In Harry Potter and the Goblet of Fire Voldemort had promised Nagini that she could devour Harry after Voldemort killed him. However, she was denied this when Harry escaped from the graveyard a bit after the promise was made.

Lord Voldemort is able to possess Nagini, which he did in Harry's fifth year, when he possessed her and entered the Ministry of Magic, and attacked Arthur Weasley, who was on watch duty for the Order of the Phoenix. Her venom, which is highly poisonous, keeps wounds open and melts stitches. It is unknown what true species of snake Nagini is, though it is said she has a hood which may place her as a cobra. Although in the films she was portrayed as some species of Python, which contradicts the book's description as a venomous snake. However, it is possible she is a fictional species of venomous python within the movie continuity. Nagini seems to be the equivalent of Fawkes, Albus Dumbledore's Phoenix, both sharing spiritual bonds with their owners.

In Harry Potter and the Deathly Hallows, Nagini is placed in a protection orb by the Dark Lord, who tells her it is for her own good, while in reality he is only trying to ensure his own immortality. Later on, while in the Shrieking Shack she kills Severus Snape, under the orders of Voldemort, by biting his neck and injecting him with her deadly poison. After Voldemort 'kills' Harry in the Forbidden Forest, she is released from the orb, as Voldemort believes there to be no more threat of her being killed. She is beheaded by Neville Longbottom during the Second Battle of Hogwarts by the Gryffindor Sword.

Since she was Voldemort's last remaining Horcrux, her death sets up the series's final climatic duel between him and Harry Potter. With no Horcruxes remaining and thus normally mortal again, Voldemort's death in that duel is final.

Trivia

 * "Nagini" comes from the Hindi word "Nagin" meaning, "Female snake".