Asterians are extraterrestrial beings from the planet Asteria.

Asterians are literally "made of magic": their bodies are not biological entities, but magical energy given physical form. Their nature as constructs of pure magic gives them immense supernatural power, far exceeding that of any human mage. Asterians are said to be nearly omnipotent, capable of rewriting the basic laws of physics that govern the universe.

Despite their seemingly unlimited power, however, Asterians seem to know little about their own origins. While they all agree that they originated on a distant planet called Asteria, none have been able to explain where Asteria is, what Asteria is like, how they came to Earth, or even how long they have been on Earth. As PrincessAlice explained: "My memories only go back a few centuries, so as far as I can remember, I've always been here. Earth is the only home I've ever known."

The true form of Asterians is not known, even to themselves. Those Asterians who have arrived on Earth have taken on the appearance of human women, though none of them seem to remember whether this was by choice or if it "just kind of happened".

• Schoolboy: If you're a magic alien from another planet, why do you look like a human girl?

• Princess Alice: Because I want to! Is there something wrong with looking like a human girl?

Because Asterians are magical rather than biological in nature, they have very few biological needs. For example, Asterians do not need to eat, though those on Earth often partake in it anyways just for fun. Even TsarinaMalice, who claims that such a lowly human activity as eating is beneath her, has been seen greedily devouring a bacon double cheeseburger from time to time. Similarly, while Asterians have no biological need for sleep, PrincessAlice was introduced to the concept of sleep by her Earth friends, and she quickly became addicted, often sleeping well into the afternoon--much to the dismay of TheHandler, especially on school days.