Nagini was the pet snake belonging to dark wizard, Lord Voldemort. She is described as a female long, green snake with a special bond to Voldemort. She had performed various deeds for the dark lord which usually involve the death of someone. With the murder of Bertha Jorkins in 1994, Nagini became another one of Voldemort's various horcruxes. Nagini was ultimately killed by Neville Longbottom in The Battle of Hogwarts, leaving Voldemort with no remaining horcruxes.
Lord Voldemort obtained Nagini sometime after attempting to kill Harry Potter. She was used to help Voldemort regain his strength and create a basic physical form and power so that he could one day rise again. By milking her venom, Voldemort was able to create a potion to sustain him until he achieved a proper physical body form. She is considered the magical familiar of Lord Voldemort and is incredibly loyal to him.
 Goblet of Fire
Sometime in the summer holidays before the start of the school year in 1994, Voldemort used the death of Bertha Jorkins to turn Nagini into one of his many horcruxes. Eventually Voldemort had a total of seven different horcruxes with Nagini being the one closest to the Dark Lord at all times. Albus Dumbledore first picked up on this and led him to think that Nagini was a horcrux. While conjuring plans in the Riddle House, the gardener Frank Bryce saw lights coming from the home. On investigating these lights, Nagini informed Voldemort of the man's presence and he was subsequently killed. 
 Order of the Phoenix
In 1995, Voldemort possessed Nagini and set out to kill Arthur Weasley who was guarding the door to The Department of Mysterious and the Prophecy for the Order of the Phoenix. After falling asleep, Nagini viciously attacked Arthur Weasley and then left him to die. Harry Potter, seeing this vision, alerted Professor Minerva McGonagall who then proceeded to tell Albus Dumbledore. Arthur was subsequently saved from death and taken to St. Mungo's where he later made a full recovery. 
 Deathly Hallows
In the summer holidays of 1997, Charity Burbage the Muggle Studies Professor is abducted and taken to Malfoy Manor. She is later killed by Lord Voldemort who then feeds her body to Nagini. At Christmas time in 1997, Nagini used extremely dark magic to pose as Bathilda Bagshot in Godric's Hollow. When Harry and Hermione arrive at Bathilda's home with who they think is her, Nagini attacks the pair and bites Harry before Hermione can come to his assistance. The two later escape by using a blasting curse and Nagini has failed her mission once again.  In 1998, Voldemort placed Nagini in a protective orb to save her from any attacks as he was trying to save his horcruxes. Later on during the Battle of Hogwarts, Nagini bit and poisoned Severus Snape under the command of Voldemort, which he then died. After the supposed death of Harry Potter, Voldemort freed Nagini from her orb and wrapped her around his neck. Voldemort asked Neville Longbottom to join the Death Eaters as he was pure-blood but he refused so Voldemort put a full body-bind curse on him and set a flaming Sorting Hat onto his head. Once Neville broke free of the bind, he pulled the Sword of Gryffindor out the Hat and beheaded Nagini, leaving Voldemort with no remaining Horcruxes. 
 Outward appearance
Nagini is described as a green viper who is 12 feet long and about as thick as a man's thigh. Being a viper she is very venomous, her venom even helping Lord Voldemort regain power and strength. In the movies, Nagini is seen as a very long, thick green viper with beady yellow eyes and yellow and green patterned skin.
 Personality and Traits
Nagini was one of the only things Voldemort actually cared about and she was completely loyal to him. She usually slithered throughout the dark lord's body and enjoyed being rather close to him, she is even seen on Voldemort's neck like a scarf. She is cunning and deceptive and often helps the dark lord's plans to capture Harry Potter. She really seems to understand Voldemort and in the way which humans behave.
She was adopted by Lord Voldemort so she could become his familiar and horcrux.
 External links
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