I dont know if they were Commissar units, but they were called NKVD troops, and they were waiting behind the lines with machine gun bunkers and barbed wire entanglements.
I think thats what penal battalions were for, commiting suicide to redeem themselves.
Is BTS going to model these? I'd feel sad sending a bunch of people with no weapons into German lines. Most of them were old men and children my age who stole food to feed their families.
Stalin was nice wasnt he?