As far as demiplanes go, Eustacius is not very large. It is more of a plane of thought, rather than
physical substance; a set of several dozen realms which are interconnected by concepts rather
than actual pathways.
A race of halflings has lived so long underground that their skin has taken on the color and texture of cauliflower, they are called the Cauliflower or the Mushroom People for their skin and aversion to light.