The giant blue aliens are back.

And this time, they’re battling a sexy, non-human baddie.

The first trailer for “Avatar: Fire and Ash,” the third chapter in director James Cameron’s 16-year-old science-fiction franchise that hits theaters Dec. 19, was unveiled to the press on Monday at Disney’s offices in New York and LA.

And the movie’s most striking addition is a freaky character named Varang, voiced by Oona Chaplin (“Game of Thrones”). 

Decked out in a spiky red-and-black headdress that brings to mind the Queen of Hearts from “Alice’s Adventures in Wonderland,” she’s the leader of the Ash Clan, a race of Na’vi that live up in the mountains around volcanoes.

Varang walks through a hot, gray landscape lit by magma and wields what looks like a flamethrower. 

Appearing to hold Jake and Neytiri’s daughter Kiri (Sigourney Weaver) hostage in the promo, Varang evilly hisses at the girl who has a special connection to the spiritual being Eywa, “Your goddess has no dominion here.”

The wicked remark suggests that some Na’vi clans worship different entities — or none at all. 

Venomous Varang would be the first full-on Na’vi villain in the “Avatar” franchise, which has so far pitted the citizens of Pandora against violent earthlings. Now, it’s the 10-foot-tall aliens that are at each others’ throats.

“Varang is the leader of a people who have gone through an incredible hardship. She’s hardened by that,” Cameron told Empire. “She will do anything for them, even things that we would consider to be evil.”

The trailer also hints at generational change.

Young warrior Lo’ak (Britain Dalton) has seemingly grown close to Tsireya (Bailey Bass), the daughter of the sea clans leaders Tonowari (Cliff Curtis) and Ronal (Kate Winslet) that he was smitten with in the second movie.

Tsiereya touches his heart and says, “The strength of the ancestors is here.” What a flirt. His parents Jake (Sam Worthington) and Neytiri (Zoe Saldaña), meanwhile, exchange parental sideways glances.

Despite its title, “Fire and Ash” also returns to the oceans of “The Way of Water.” The whale-like Tulkun creatures are back. And so, of course, are the scaly flying Ikran.

A cool new mode of aerial transport we haven’t seen before is revealed in the trailer — giant jellyfish-esque sky-ships that are pulled along by floating hippos.

It’s unclear when the “Fire and Ash” trailer will drop publicly, but Disney has a major wide release coming this weekend with Marvel’s “Fantastic Four: First Steps.”

“Fire and Ash,” out Dec. 19, is one of the most hotly anticipated movies of the year. The first two chapters are respectively the No. 1 and No. 3 highest grossing films of all time — having raked in $5.2 billion at the worldwide box office.

Both were nominated for the Oscar for Best Picture, and the series spawned a successful theme park at Disney World’s Animal Kingdom in Orlando, Florida.

Cameron currently plans two more “Avatar” films after “Fire and Ash,” due out in 2029 and 2031.