Hailing inward, from the center of the flat plane, the homo robustus, or... dwarves, have a shorter stature that is in return compensated by their dense physique. Similar to sapiens in many regards, although obviously shorter, they do however possess some unique aspects. Their bones are as hard as steel and their strength and endurance outperform many creatures of a larger size.
However, even though they may resemble their sapien brethren, their origins is still shrouded in mystery. On one hand, they could have developed their physique from the increased gravitational fields in the center of the flat plane. On the other hand, this might just be coincidental, as they also exhibit features unlike the other humans; like a much more extended age span, stronger constitution against poisons and a psychologically and overall personality that tend towards a structured role-centered society, leaving little room for creative thought.