Watching Inglorious Basterds the other day, I thought "Why the fuck didn't they try something like this irl?" It's a good question, the Nazis used intimidation and terror to conquer most of Europe from 1938 onwards, hell the Waffen SS was literally an army of psychopaths created to wipe out the Jews of Europe and murder a good portion of the Slavs, so why didn't the WAllies try to terrorise them back?
I have seen some examples where the Allies basically become desensitized to violence over the course of the war and start cracking skulls in occupied Europe, but that's only in a few TLs. Calbears Anglo-American Nazi War and For All Time show this through the use of chemical, biological and sometimes nuclear weapons on Nazi Germany, and whilst that is in a similar train of thought to what I'm talking about, it doesn't exactly cover it.
The closest thing I can think to something like the Basterds is SOE agents who worked with Resistance movements behind enemy lines. Whilst they did help with many assassination attempts on Nazi High Command, including the death of Reinhard Heydrich, they still don't cover what I mean. Namely groups of men, dropped into occupied Europe with the purpose of terrorising occupying German forces and local collaberators for as long as they can. Assisting Partisans is all well and good, but it won't scare anyone in Berlin, Warsaw or Vichy. Murdering entire units of soldiers in cold blood, torturing prisoners and being generally ruthless however does.
So is there anyway to make something like this possible, or is it just Quentin Tarantinos pipe dream?