Astrolea is actually a goddess, though she doesn't like to define herself as a goddess due to the fact that gods and goddesses generally have a bad reputation. Astrolea's box is a closed-form pocket universe that contains only the worlds and the resources they need to survive. It's described as dark, sometimes creepy, but ultimately a safe. Even though she is already colossal compared to her worlds, when she places them in the box, she shrinks them several million times more for all worlds fit.