Dark sun that isn't actually dark sun.
The mother of the drowned, Ulbecetonth has a warm motherly voice, and is worshipped by her children, the Abysmyths. Ulbecetonth’s attempts to invade the material plane were prevented by the heroics of The Competent Adventurers
Abysmyths are immense bipedal creatures, resistant to mortal weapons but utterly terrified of fire, which is anathema to them. They are capable of drowning people on dry land by secreting a liquid through pores in their hand.
The drowned men are enslaved beings. Referred to as frogmen, they are rubbery to the touch, with dark eyes and sharp teeth. Their only pleasure is serving the Abysmyths.
Ulbecetonth and her children currently reside in The First Circle of Hell, The Skybound Sea.
Artist’s rendition of the Abysmyth leading the drowned