This is the queen mother, who exists at the center of the universe.
And yet, somehow, we're not talking about Beyoncé.
Mainly because, while Queen Bey does exist at the center of the universe, she's not playing a subordinate role to the Hero. She's her own dang hero.
The function of the Queen of the World is being the regal lady who holds all the keys to all the things the hero has ever wanted. We'll let Mr. Campbell put it in his own words:
The ultimate adventure, when all the barriers and ogres have been overcome, is commonly represented as a mystical marriage of the triumphant hero-soul with the Queen Goddess of the World. (100.2)
There's a reason we call the figure a goddess instead of a god. Mom's an important figure in our lives, and Campbell knows all about it. (Psst: Campbell was a Freud fanboy.) Check it out:
The mythological figure of the Universal Mother imputes to the cosmos the feminine attributes of the first, nourishing and protecting presence. The fantasy is primarily spontaneous; for there exists a close and obvious correspondence between the attitude of the young child toward its mother and that of the adult toward the surrounding material world. (103.4)
The goddess can sometimes turn on the hero, in which case that hero is 100% doomed. But that's okay: like the whole universe she represents, she has both a light and a dark side, and it wouldn't be right if the hero experienced one side but not the other.
The moral of this story? Don't mess with the Queen.