Ok this is not confirmed and nobody will ever confirm.
As I heard that Greystone mercenaries (ex SEAL, SAS soldiers) (the infamous Blackwater in Iraq) are helping the Ukrainian army dressed up in SOKOL special police force (like the US SWAT) (Font German Bild magazine – naturally denied by Greystone) – I always wondered who was on the other side…as they were particularly good at their job.
Finally I found that TIME interviewed the other side, the commander of the paramilitary force Wolves’ Hundred (so called because their famous Russian cap is made of wolf instead of sheepskin.
They would be the real “Inglorious bastard” of the Quentin Tarantino movie.
As a unit they were founded by the Czar Nicholas II and their motto was to defend Mother Russia and the Orthodox Church with any mean at any cost. They fought alone for 2 years against the USSR after the fall of the CZAR.
Then they got dismantled, some units still remained due to their ferocity and used as punitive squadrons to be inserted behind Germany Nazi lines to kill and be killed (as they were always outnumbered and would be shot if they returned to the USSR). Naturally they did it with extreme diligence and violence – practically against anyone they met (Germans, civilians and Russian).
Putin reinstated them in 2005 as a paramilitary unit (so it is deniable), even if they paycheck comes from the Russian states.
Since then they always been deployed in the worst conflicts like Checenya and going on with their job.