Character from harry-potter-deathly-hallows by
Voldemort's enormous snake familiar and final Horcrux -- she carries a piece of his soul, kills on command, and is destroyed by Neville Longbottom with the Sword of Gryffindor in the battle's climax.
Nagini is the last Horcrux. She killed Snape in the Shrieking Shack on Voldemort's orders -- he set her on his most loyal servant because he believed killing Snape would transfer the Elder Wand's allegiance. She was disguised as Bathilda Bagshot at Godric's Hollow, ambushing Harry and Hermione inside the old woman's body. She nearly killed Arthur Weasley at the Department of Mysteries. During the Battle of Hogwarts, Voldemort keeps Nagini close, protecting her with an enchanted bubble. When Harry reveals himself alive and Voldemort's Killing Curse rebounds, Neville pulls the Sword of Gryffindor from the burning Sorting Hat and beheads Nagini in a single stroke. The final Horcrux is destroyed. Voldemort is mortal. The war ends.
Enormous green snake, twelve feet long, thick as a man's thigh. Glittering dark eyes with vertical pupils. Moves with terrifying speed and silence. Protected by an enchanted bubble of magical shielding during the battle.
Also known as: Nagini, the snake