There's also a major reveal about the true identity of the Maledictus (Claudia Kim), an individual that suffers from a "blood curse" that turns him or her into a beast, which is something that has long intrigued fans since hearing details of the Crimes of Grindelwald. In a franchise that has frequently been criticized for its lack of diversity, one of the few characters of color is now doomed to become enslaved by a villain who is a thinly veiled Nazi metaphor. She was even able to wear the body of Bathilda Bagshot like a puppet and nearly lure Harry and Hermione to an early grave in The Deathly Hallows.
Nagini's character will be played by Claudia Kim, who before now had been credited with a nameless character for the upcoming film. However, even with the story being set in the same universe, The Crimes of Grindelwald is itself a unique story, something that the cast and crew have already begun to tease.
Until now, marketing for the movie continued to keep everything else about the character a secret, fuelling speculation that this wasn't just any snake girl but, in fact, was the future familiar of He-Who-Must-Not-Be-Named.
After almost a year of speculation over whether Fantastic Beasts: The Crimes of Grindelwald will delve into Nagini's origin story, a new trailer for the movie has confirmed that the human version of Voldemort's beloved snake is set to make her grand wizarding world entrance. Very little was known about Nagini's life prior to her appearance in The Goblet of Fire, a life which we now know spanned about 70 years.
Also, the EW article linked above says Nagini "has powers like wizards have".
This Nagini is part of the Circus Arcanus with Credence Barebone (Ezra Miller), whom we know to be an Obscurus whose magic sometimes loses control and bursts forth, often leading to destruction.
Are you going to see this film when it releases? Dumbledore told Harry, "I think he is perhaps as fond of her as he can be of anything". Kim is vague on whether Nagini is a witch herself, which is unclear as she doesn't wield a wand, but carefully elaborates that "She has powers that are yet to be explored".