Liliths as I'll proceed to call them seem to be the dominant species in this world. They are slender and extremelly tall.
The Boy on the other side are the working class. They mainly spend their time scavenging for technology they can hand in to the Liliths in exchange for momentary validation. This is exemplified in the image via the protagonist giving in a working microwave in exchange of attempting to highfive Miss. "Lilith". The Boys are half the size of Liliths, but seem to posses great physical fitness as demonstrated by the height of the vertical jump shown in the image.