It’s actually a quirk of the fact that al-Merayah has a treasure coffer. I don’t have one and they’ve been periodically spawning after I assaulted al-Merayah to farm some hardened steel from enemies’ dead bodies/weapons.
omega LOL
btw they not purge npc but al-Merayah defenders but how they ended there? some expectional bug that stygian base defeners sink into ground texture and exit inside klael? or when they die in fortress they reincarnate inside klael? or very mean hacker was angry and spawn stygians just for malice.
It’s definitely not exceptional, I currently have to build my structures in my single-player game anticipating possible approach by these guys because it’s so common.
The only possible indication you get there’s a raid incoming is that they get vomited out of the sky in large groups like the one you see at the gates of the fortress and start running in a random direction. Where they run is not going to be where they end up - they somehow found a way on top of the gigantic bridge/dam ruins once. I sneakily followed them and they just vanished into thin air and I thought nothing of it, until I got to my base and saw them in one huge ball just waiting on the bridge. At least I could kick all of them off.