Guardians of the Galaxy: Volume 2 could have easily rested on its laurels and just stuck with the cast of the first film, but the movie wanted to do something different. As a result, there are a number of new characters introduced, like Ego the Living Planet, Mantis, and the Sovereign Priestess, Ayesha, played by Elizabeth Debicki. She's one of the main villains in the film, but just who is the Priestess in Marvel Comics?
In the movie, Ayesha is the leader of a golden alien race known as The Sovereign. They are obsessed with perfection, and Ayesha believes herself to be an example of that perfection. This idea has its roots in Marvel Comics, but the Sovereign do not. Like the Ravagers, the Sovereign don't actually exist in the comic books. They are an invention of writer/director James Gunn, who uses them to explain Ayesha's origin in a way that fits in better with the Guardians' universe. Ayesha has been a character in the comics since 1977, and while she looks similar and has similar traits (golden skin, meant to be a perfect being) to her film counterpart, her origin is actually very different. Mainly because the Ayesha of the comics is from Earth.
In the comics, a group of scientists known as the Enclave set out to make the perfect human. The result was Adam Warlock, who quickly fled Earth for outer space and has since become one of Marvel's premier cosmic characters (he's also set to appear in Guardians of the Galaxy 3). Frustrated, the Enclave tried again, and the result was the being who would eventually go by the name "Ayesha," though she's also gone by the names "Her," "Kismet," and "Paragorn" (never has she gone by "the Priestess," though).
In the comics, she's been both a hero and a villain, but her main goal throughout her history has been to create a race of perfect beings (similar to the Sovereign of the film). To do this, she scopes out the superheroes of Earth for good mating potential, and at least temporarily settles on the cosmic hero Quasar. In an alternate timeline, Ayesha and Quasar actually sire a child, Stakar, who goes on to become the Guardian of the Galaxy Starhawk 1,000 years in the future. Stakar is in the new movie — played by Sylvester Stallone — but he does not have the same origin... at least I don't think he does.
Despite existing in one form or another in Marvel Comics for 40 years, Ayesha is a little-known and little-used character. Because of that, Guardians of the Galaxy: Volume 2 had pretty much free reign in creating her, and they used it to its fullest extent by making her the leader of a brand new alien race. And I think it's safe to say that the Ayesha of the movie — not of the comics — will be the one that most Marvel fans think of now.