From 1d4chan

One of the races from the Warpath setting, Nameless are the other thing that happens when Tyranids gain sentience(the other beign the Z'zor), and they are fucking broken in nearly every game they appear thanks to their variety of options.

Many things are not known about the nameless. What we do know is that they aren't a single species, but rather a confederation of at least 5 different squid and crab like people. And since Warpath loves to twist classic tropes, the one group that look like a collection of lovecraftian abominations are very fond of cooperation and living in harmony.