No, Nagini is not a Basilisk. While Nagini, like the Basilisk, is a snake and responds to Parseltongue, she is not a Basilisk. While Nagini resembles a python in the movies and the books, in the Harry Potter prequel series, Fantastic Beasts and Where to Find Them, it is shown that Nagini is a woman with a blood curse.
Nagini has been described as multiple real-life snakes, including a Reticulated Python, a Dumeril's Ground Boa, and a Burmese Python. Although she shares traits with all three, none of these animals are inherently venomous. As mentioned earlier, Nagini's venom is an iconic facet of her character.
Nagini is one of many snakes featured in the series
After all, the great Basilisk in the Chamber of Secrets was a huge snake, bred with Salazar Slytherin's intent to murder Muggle-borns. The Dark Mark, Lord Voldemort's 'sign', was a skull with a snake tongue.
It's later revealed that Nagini was never an ordinary magical snake from start, as she was once in fact, a human (possibly a Witch) who became a snake as she is now as result of a blood curse and trapped in that form for the rest of her life.
Because Nagini also happens to be the name of another iconic “Harry Potter” character — Lord Voldemort's magical, extremely murderous pet snake. Well, just in case there was any doubt, “Harry Potter” creator JK Rowling confirmed the two characters are one and the same.
Voldemort had a special relationship with Nagini, as she was his pet and one of his Horcruxes. According to Dumbledore, Voldemort had strong feelings for Nagini that he had not for anyone else; she was the one living thing that he had ever cared about.
Dumbledore does not use any language to make one think that Nagini is anything more than a snake. But this could be despite his knowledge of Nagini's past because he has to factor his grand plans into everything he tells (or doesn't tell) Harry.
In short, no one knows exactly how Nagini ends up as Voldemort's closest ally. Evidently, something happened between the time of her joining Newt and the events of Harry Potter that pushed her to the dark side. She might even have met Voldemort while still human, and he was Tom Riddle.
When Harry and Hermione are on the first floor of Bathilda's house, Nagini (inside the corpse of Bathilda) tells Harry to "Come!" from the next room in Parseltongue. In reaction, Hermione jumps and clutches Harry's arm, and the two of them obey the command.
Nagini, it turns out, was actually a Maledictus—a witch with a blood curse that turns her permanently into a beast (in her case, a giant snake). In the film, the witch is played by Claudia Kim.
It wasn't just inanimate objects that could become Horcruxes. Lord Voldemort's beloved snake companion, Nagini, was also transformed into one, and Dumbledore seemed to know it, ominously predicting that a day would come where Voldemort would 'fear for his snake'.
Nagini is loyal to Voldemort because he can speak with snakes. As a Maledictus, there probably isn't much time after the events in The Crimes of Grindelwald before Nagini falls to her blood curse, becoming a snake forever.
Deathly HallowsEdit
Nagini, Voldemort's snake, then eats Professor Burbage's dead body. A story about her "resignation" from Hogwarts appears in the Prophet, but members of the Order of the Phoenix discount it, as they are unable to locate her anywhere after that.
Though it may later be revealed that the Dark Lord did indeed know that Nagini was a Maledictus, there's currently no indication that he (or anyone else) ever thought that she was anything other than a snake who was made into one of the Dark Lord's Horcruxes.
"In her name — because the Naga are, in mythology, a race of snake beings. So the name was an allusion to the fact that she may herself once have been human." Nagini is revealed as one of Voldemort's horcruxes in "Harry Potter and the Deathly Hallows." Warner Bros.
As J.K Rowling revealed, Albus Dumbledore had mastered Parseltongue too – although he could not speak it aloud.
Voldemort orders Nagini to kill Snape, and the great snake bites Snape's neck, mortally wounding him.
But JK Rowling tweeted that Nagini is based on "the Naga", which are "snake-like mythical creatures of Indonesian mythology." She added: "They are sometimes depicted as winged, sometimes as half-human, half-snake. Indonesia comprises a few hundred ethnic groups, including Javanese, Chinese and Betawi."
It is very possible that J. K. Rowling did say this, but that she was referring to the snake actors in the movies, not the characters. This is NOT true. The quote was started as a joke on tumblr. Besides, Nagini is a viper (a venomous snake), and the snake Harry set free was a boa (a constrictor, not a venomous snake).
Credence Isn't Voldemort's Dad But He Could Be Snape's Grandpa.
Credence may well be related to Voldemort, but it would have to be through Voldemort's grandmother. That also means the mystery woman must've had a second child: Merope Gaunt, born in 1907. It's entirely possible that Aberforth could have sired a child with Voldemort's grandmother.
The escaped boa constrictor in Philosopher's Stone wasn't Nagini. It was never Nagini. That's an incorrect but very persistent fan theory!
In the movies, Nagini was the one who killed Snape in the boathouse. The Maledictus meets her end when Neville Longbottom finds Gryffindor's sword and, in an attempt to destroy the final Horcrux, cuts off her head.
After Voldemort was gone, Nagini decided to follow her dreams. She went to Brazil to join other snakes in the Amazon rain forest. While there, her adventures with Voldemort inspired her to write a song in Parseltongue called "I Thought You Were Pretty Cool But Then You Couldn't Even Defeat a Baby.
Voldemort intentionally made six Horcruxes, but when he used Avada Kedavra on Harry, he unintentionally created a seventh Horcrux. Instead of dying, Lily's love for Harry created a counter 'curse' known as Sacrificial Protection and saved Harry.