Wonder Woman 1984 built up the lore of Diana of Themyscira, but it also served to add something that seemed new to her story. Amidst the troubles of Maxwell Lord and Cheetah, Diana was also involved in a decades long search for a missing Amazon: Asteria. She was the one Amazon who chose to hold back the armies of men as her sisters escaped to their new home. For this apparent sacrifice, Asteria was honored by the Amazons, but Diana correctly suspected that she was still alive somewhere.
While this character may seem new to the history of the DC Universe, there is a version that exists in the comics. But her origins are quite different from than that of her cinematic counterpart's.
The Asteria that appears on the big screen has a more fleshed out backstory than her comic book counterpart. In fact, it would be fair to call the comic book version a blank slate, the foundation from which the movie version would be built upon. She first debuted in Elseworld's Finest: Supergirl & Batgirl #1 by Barbara Kesel, Matt Haley, Tom Simmons, and Bill Oakley. Much like in the movie, this Asteria was connected to the Wonder Woman of her world.
In this alternate reality of Earth-1098, Wonder Woman was the leader of the Justice Society of America in the modern day. It's members included the likes of Supergirl, Ambush Bug, and Captain Marvel (before the name change), and these were the members that came with Wonder Woman to Gotham City, Asteria was left in charge of watching the team's base of operations, along with watching their resident guy, or more precisely kid, behind the chair: Tim Drake. Not the most glorified position, but it shows the level of trust that Diana had in Asteria by trusting her to watch the base. It also subtly hints at Asteria's true power, considering she was left at the base alone to protect Tim.
Very little was revealed about Asteria. She only really appeared in a handful of panels in the comic, but she demonstrated the ability of flight. While some Amazons can fly, Asteria's limited time in the spotlight only leads to speculation about her origins in comics. She never outright stated that she was an Amazon nor did she say wasn't. So for the most part, the first Asteria was more of a question mark than a character, but the many questions surrounding her origins gave her the opportunity to star in one of 2020's most anticipated movies.
In many ways, being such a blank canvas was good for Asteria. It give the character a chance to shine while still holding true to the lore of the DC Universe. Moreover, Asteria's new origins are inspiring enough to potentially be translated over into comics. Very little is known about the time when the Amazons first retreated from Man's World. Even if the story of how the Amazons first entered Themyscira differ from that of the movie, Asteria has now been permanently tied to the origins of Paradise Island and has a much greater role to play in the future of the DCEU, if not also in the comics.