Based on current evidence, my theory is the Volcano Island in Medici.
See also: The burning of the north.
(Not exactly a good thing for those wondering what "burning things" means)
This burning of the north thing is kind of dumb, because of that, the north of Insula Striate feels empty... and there is so much place to put cities there...
Yeah. The burning of the north could easily have covered less area. Maybe the wall could still be there, but most civilian settlements there would just be abandoned.
Isn't there a Black Hand quote where they say the wall was created to stop citizens from interfering with military affairs? The burning of the North may have been just been to create a militarized zone, and the destroyed military vehicles are from rebels fighting back. It seems plausible to me that someone could steal explosives and destroy a CS Odjur. This is a sadistic dictator we are talking about, burning dozens of villages to have more secrecy is perfectly reasonable to him.
Reactivated 40 days later
...where exactly did you hear this quote?
Learned it from the wiki (Black Hand in JC3), so I can't confirm myself. Apparently Black Hand conversations are very hard to hear, according to the same article, and you have to set up circumstances like making them get in vehicles with other soldiers.
I suppose they could possibly be over-heard if the player can find a place where they won't get heat and where there are at least 2 of them with in taking distance of eachother. Otherwise characters (Rebellion) are known to talk to eachother when they're in a car.
Medici Military soldiers can be heard talking to eachother at several small outposts, but I don't know of a good way to get the Black Hand to talk to eachother.
I think you'd have to lure them out of the base by getting heat near a base with Black Hand and getting them to chase you, then escape heat without going far enough away that they despawn. I did have a Black Hand soldier get in a CS Baltdjur and head to where I was at the checkpoint on the road to Alte Potentia. You would probably have to open the gate at some bases, and it would require multiple Black Hand to get into the same vehicle in the first place. It is definitely possible, just difficult.
Wait, there is that one unnamed mountain that spawns Black Hand instead of Medici Military if you have any of the three DLC packs. I don't have the DLC and probably won't get it for a while, but it does seem like an easy place to hear a conversation.
What do you think?