Rise of the Flayers
Illithids are the most commonly known of all the Aberrations. They had a massive Empire thousands of years ago, but it was overthrown by their slaves. They now live in small pockets around the multiverse in the various worlds and Material Planes. They are powerfully psionic and are capable of destroying many without lifting a finger. They feed on brains, and often leave entire villages a wasteland. For an unknown reason, they only reproduce successfully with Human hosts. They reproduce by putting a small worm into the ear canal of a Human, preferably an intelligent one.