Name of Group: Polski Korpus Wyzwolenia (PKW) Polish Liberation Corps (PLC)
Their military arm is known as ‘Peklenc’, named after a cthonic Slavic diety who was both lord of the underground and a divine judge, said to be purely fair and equal in judgement, and also responsible for ousting unjust leaders.
Type: Polish independence/violent opposition to German government
Assets: Numerous, though the PKW's power is almost entirely confined to Poland; despite this, small armed cells do exist in Germany itself. The PKW operates primarily from high-density urban districts, oftentimes making use of abandoned warehouses or other large structures are headquarters for its personnel. Certain underground cells also operate from tunnel networks under the cities, usually consisting of complexes dug throughout unused, abandoned, or older sewer systems. Weapons are both purchased illegally and produced. Personnel: Numbers unknown, though the organization is primarily composed of Polish veterans, former Polish politicians, pro-independence civilians, and a small number of Polish businessmen and scientists who silently support the PLC. The PLC possesses a number of Polish military vehicles and weapons that survived the war, and seeks to recover leftover caches of Polish weapons that were lost to the Germans.
History: The PLC is, arguably, one of the most prolific and outspoken resistance movements of the post-WW3 Earth. It has origins tracing back to the week after the Polish government's forced surrender to Germany, which saw multiple uprisings across the country in retaliation to the German invasion. Androvsky Krylowov, a former officer of the Polish special forces unit known as GROM and an outspoken Polish political nationalist, delivered a speech to thousands of protestors in Old Town Market Square, Warsaw, calling for the Polish population to fight for its freedom - to make it clear to Germany that they would not simply bow before hostile invaders. He enraptured the crowd with his words, emphasizing his desire to give his daughter a future outside of being a peon of the German government, and declared that he would stop at nothing to bring Poland freedom.
After multiple failed attempts to negotiate Polish independence, Androvsky vanished from the public eye, declared missing by authorities. A few weeks later, he illegally broadcasted a message to his supporters that he would be forming the Polski Korpus Wyzwolenia, a resistance movement that would use both violent and peaceful methods to achieve Polish independence. German police immediately began a manhunt for Androvsky, though the majority of police and counterterrorist raids on PKW facilities ended with heavy casualties on both sides. Eventually, the PKW began to expand its operations, even targeting German military bases and depots, including causing prison breaks where Polish POWs or political prisoners were held.
The PKW eventually expanded its operations into high-profile assassinations mirroring Operation Heads of WWII. These assassinations almost universally targeted German officials or Polish collaborators that directly opposed the PKW, cementing the PKW's dedication to the removal of German rule, rather than being a group that targeted civilians or purely sought to cause terror. Most strangely, the PKW would occasionally hold Polish cultural festivals and provide aid to the unfortunates of Poland, even despite its harsh actions towards the German government, further growing civilian support and increasing sympathy towards the organization.
Drazenka Krylowov, Androvsky's daughter, has also made clear her adamant support for the PKW, and oftentimes serves as the organization's poster-girl due to both her impressive fighting skill and her renowned beauty. Androvsky, due to his increasing age, grooms his daughter to replace him in the event of his death, and wishes to die with a bang in order to live on as a martyr after his death. Drazenka did serve in GROM during the war (though obviously not under her father), owing to her wide range of refined skills.
Similarly to the Polish Home Army, the PLC engages in the manufacture of its weapons, in addition to receiving weapons from outside sources. Due to their current situation, heavier and larger vehicles are few and far between, while aircraft are incredibly sparse in their use. Light vehicles, in contrast, are much more frequently used and produced, along with the occasional improvised urban combat vehicle or artillery piece.
Above all else, the PLC is widely known to be a highly dangerous and persistent group of rebels. They are known to engage in revenge killings against German government or military officials in return for the deaths of fellow rebels or Polish civilians, and are known to publicly display lists of civilians killed by German government actions, along with the German official that was killed in retaliation. Regardless of whether or not the death was accidental, the PLC almost always reacts harshly to civilian deaths, using them as an effective fuel for their revolution and as propaganda to boost recruitment. The PLC also carries a policy of ensuring proper burial for civilians killed, and does not publish the names of civilians without permission of their next-of-kin or immediate family (in an effort to avoid agitating civilians).
The PLC is also a revolutionary group that follows a strict moral code, which is as follows:
Civilians may not be killed, except in the defence of oneself or others.
Looting of non-collaborator civilian property is not permitted.
Use of NBCs is not permitted.
Free speech and intellectual discourse is encouraged. Do not stifle the opinions and views of others.
Do not involve our movement with third parties without permission from our leadership.
All religious or non-religious views are permitted, as long as they do not violate our tenets or damage our cause.
Liberation of Poland from all foreign governments is our one and only goal.
Romantic or sexual relationships of any kind are permitted, as long as they do not damage our group, violate our tenets, or distract from our goal.
Cruel and/or unusual punishment is never permissible.
Stealing from weapons, vehicle, or food storage is not permitted and will be severely punished.
All those who wish for the liberation of the nation of Poland are allowed membership after background tests and the appropriate testing.
Freedom of Poland, revival of its culture, and the liberation of its people are our prime goals. This must be accomplished at any cost.
On the topic of armor, you guys should look into the Future Force Warrior program. Plenty of cool stuff there. I'd also generally look into the DARPA projects as of late. They are developing more basic exoskeletons, and tons of other stuff. Wikipedia has a comprehensive list. Outside of DARPA, too, there are numerous research groups that are developing stuff like prosthetics that can be controlled with the mind - tons of actual stuff to work with.