I've been curious about writing about a very durable exoskeleton humanoid species, but I have wondered about how the extra weight of a thick exoskeleton would affect their height.
I do not see them as 'prawn like' insect-like creatures (like from District 9). Instead, the prehistoric armored fish would be a closer relative for the general make up of their thickly armored exoskeleton while retaining bipedal mobility.
The main idea is their exoskeleton is some sort of ultra-dense variation of our bone material, thickness tbd, maybe 5-10mm, and effective armor against any bladed weapon and many pistol and submachine gun rounds.
Side Question: The skeleton a human male weighing 200 lbs is supposed to be about 15% of that body weight, or 30 lbs...your skin is supposed to weigh another 15% or so, so another 30 lbs, that would leave 140lbs of guts for a 200 lb endoskeleton male. Anyone have any good guesses of what an 8mm thick complete human exoskeleton would weigh on top of the 140 lbs of guts?