Aboleth
From Marillia
Aboleths, also known as alghollthu masters or the deep masters, are a species of hyper-intelligent psychic alien fish older than the gods.
Aboleths are, according to many accounts, the big daddies of the aberrations. There are many rumors which speak of how the mind flayers, beholders, cloakers, chuuls, and other aberrant horrors were engineered by the aboleths.
These mean fishy boys are some of my favorite monsters in the game.
Name
According to scholars on Golarion, aboleth is the term the aboleths use to refer to themselves, and it translates roughly to master or god.