Dzaal

This has always been a quiet village, so when I woke for my midnight readings, I didn't think anything was wrong. There were no screams, no feet trampling, nothing of the sort. After a bit, I stepped outside to relieve myself and saw something step out of the Karis house. It didn't look like Mita or Forsha, so I peered a bit closer and caught a look at it dragging the top half of Forsha out of the house with one set of its arms. Its eyes glinted and glowed purple in the moonlight. I ran, mister. I ran as far and as fast as I could. When I came back in the morning they were gone, but everyone was dead. Everyone. All that was left was legs and blood trails, heading to the Machine.

What's the difference between an abhuman and a mutant? Aeon Priests might argue about the finer points, but most people know - if it can sit and have dinner with you, it's a human. An abhuman has gotten rid of everything that makes it a man or a woman. It doesn't think like a human or a varjellen  - it thinks like something else, something more alien than the actual aliens.
The dzaal are a tribe of abhumans who once lived in The Empty Machine, until they were evicted and disappeared from the plains. They have four arms, teeth they file to a point, venomous slober, and glowing eyes that have perfect night vision. A horde of them is crossing the plains, looking for a new home, devouring everyone they come across. The nomads avoid them when possible, but folks in settlements aren't so lucky. They come silently and kill quickly, leaving no survivors. For some reason, they have no interest in eating or taking the legs of their victims, which they leave littered around their raid sites.