so the reason tetraspaces adopt human forms is to communicate with humans. "their" "goal" is to find the strongest million or so humans, implant them with tetraspace eggs, they fight to the death, the ~1% who survive get to be the new tetraspaces, repeat
top 50% or so of tetraspaces (who try to look like humans) have no problems w/ this. they just look like glowy floaty humans