The second film in the series, written by Harry Potter architect, J.K. Rowling, revealed in a trailer that fans had been on the right trail. 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).
But now we know Nagini was no simple supervillainous pet, but a human woman cursed with the “Maledictus” blood curse, which, according to Rowling, is a female-only inherited condition which grants the affected individual the ability to transform into an animal at will, until one day, the transformation becomes ...
This was an ability the Circus Arcanus took extreme advantage of. Ultimately, however, Nagini's Maledictus blood curse took over, which forced her to stay in her snake form permanently.
Nagini's Future After The Fantastic Beasts Movies
Between Fantastic Beasts 3 and the primary Harry Potter timeline, Nagini transforms from human to snake, but not much is known about when Nagini makes the permanent change and how her Maledictus curse takes over, erasing her human form forever.
Rowling previously revealed that Nagini is a Maledictus, which means she carries a blood curse that will doom her to transform permanently into a beast.
Nagini seemed integral to Lord Voldemort's survival before he could be restored to his body, and we learnt, quite grotesquely, that Voldemort even tasked Wormtail to 'milk' Nagini so he could live off her venom to keep his strength up. BFFs forever.
In order to get her venom, Pettigrew had to milk Nagini for it. However, milking a snake is done via the fangs by having them bite a latex cover over a glass jar, then stimulating the venom sacks by either manually massaging them or using electricity to make the muscles contract.
The canon sources do not suggest that Nagini is invulnerable to Avada Kedavra. So yes the Killing curse should be enough to destroy the Horcrux in Nagini, as that would destroy her beyond repair.
Her body disappears and gives way to Nagini, while Hermione finds what seems to be the snake's changed skin. Nagini's impersonation of Bathilda is, nevertheless, an intended trap by Voldemort for Harry, which might have put his most important Horcrux in jeopardy.
Unless one or the other has a significantly smaller role in the films than we are led to believe, Dumbledore and Nagini will get to know each other. From the very little we see of Nagini, it looks like she's at least potentially on the same side as Dumbledore.
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.
At the end of the last film, Grindelwald told Credence he was really Aurelius Dumbledore – the previously unheard of sibling of Albus. However, that wasn't entirely true. While Credence is a Dumbledore, he isn't the brother of Albus, Aberforth and Ariana. In fact, he's Aberforth's secret son!
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.
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).
So it's possible that Nagini met Tom Riddle in his early years of rising to power but by the time she found him in Albania she had been cursed to become a snake entirely, and losing the ability to turn back into a human.
Nagini is Voldemort's familiar, as well as a vessel for a slice of his soul. If she didn't house a piece of him, he might not be so fond of her. However, having the ability to speak the language and communicate with her, probably helps a great deal. He could potentially discuss any range of topics with her.
In the belief that the Elder Wand will grant its allegiance only to one who has slain its previous owner, Lord Voldemort has his pet snake, Nagini, kill Severus Snape.
In Harry Potter and the Deathly Hallows, Voldemort thinks that killing Snape will give him full control of the Elder Wand. He uses his snake, Nagini, to kill Snape rather than any number of spells he knows. This allows Snape to live long enough to help Harry defeat him.
Fantastic Beasts: The Secrets of Dumbledore finally revealed that Credence (Ezra Miller) is Aberforth Dumbledore's (Richard Coyle) long-lost son, but his mother could very well be a Gaunt, making Credence related to Voldemort (Ralph Fiennes).
In order to conjure the avada kedavra curse, you have to want to kill your victim. We all know that Voldemort could easily kill a child without an ounce of remorse... but not Snape. Snape didn't want to kill Dumbledore, and this was why the spell was blue instead of the usual green.
None of the good guys dare use the Killing Curse throughout the events of the movies and books, no matter how high the stakes and how difficult things are. But Ron Weasley is the exception, giving it a go in the Deathly Hallows: Part 2 movie when himself and Hermione look destined to die via Nagini.
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. Burbage is later replaced as Muggle Studies teacher by Alecto Carrow.
The last time he sees her, she's with Voldemort and he has to play dead, so no talking there. Plus, she has to die to defeat Voldemort.
Nagini was a maledictus. That means that she carried an innate, hereditary blood curse giving her ability to transform herself into snake, which gradually became uncontrollable until Nagini eventually lost the ability to turn back into human completely.