From publisher blurb:
You’re Gonna Need a Bigger Boat!
With their potent ability to enslave minds, and their body-altering mucus that transforms hearty adventurers into sniveling skum, aboleths may very well be the most terrifying monsters beneath the waves, even if they may not be the most powerful. And with their civilization predating most humanoid races’ very existence, and their close ties to famous lost civilizations in certain campaign settings, aboleths are also a source of mystery and intrigue. It’s only natural that many GMs would want to feature them as masterminds at the end of long campaigns, or trot them out to put high-level PCs in their place. The only problem is that aboleths are relatively low-CR.
This book presents a trio of advanced aboleths, which can strike terror into PCs at any level in the game. First is the aboleth deceiver, a sly CR 12 aboleth who makes use of a variety of mind-affecting magic found in Pathfinder Roleplaying Game: Ultimate Intrigue and Pathfinder Roleplaying Game: Horror Adventures, and which can release psychotropic ink that blinds foes and makes them more vulnerable to its trickery. Next is the aboleth dominator, a CR 17 aboleth that is a master of mental control, sapping a creature’s mental resistances with its slime and then manipulating their body like a meat puppet. Finally, the aboleth slimelord is a CR 22 aboleth that can produce a wide range of mucuses with different effects, and can bend oozes to its will.