Bonjour .
I actually met naked fighters among the Stygian soldiers.
As said above by @glurin these fighters are called “forcibly recruited prisoners”.
on a level 10 purge I had 5 to 6 waves of “prisoners” the other raiders were all Stygians in Stygian armor.
I am on a private PS5 server (so no mod) where there is total nudity, however I don’t know if on public servers where there is no nudity these “conscripts” are naked.