A little bit down the river from the Home of the Muck Dwellers is the Water Temple – where the Frog Priests cultivate their mutant frogs and worship foul gods of the depths.
Guarded by a few elite mercenaries of the fish-people, and only rarely visited by any of the strange jellyfish beings from the node to the north, this node is almost entirely given over to the frog folk, their spawn, and a pair of spirit naga who have placed themselves as the intermediaries between the frog folk and their squamous deity.
Having seen the frog folk experiment on their giant frog companions, the spirit nagas have hatched a plan for expanding their sphere of influence further into the Delve. They have collected young from the otyughs in the Lost River node and have begun experiments creating neo-otyugh that are under their control, which they will have seeded into other areas by fish folk mercenary units.
The young otyughs are cared for on the backs of specialized mutant giant frogs who glue them there in their eggsacs from whence they eventually hatch and are fed by the frog priests.
The two elder jellies who live in this area are magically enslaved to the naga, and rarely if ever venture back to the home node, providing their spellcasting expertise to enhance the genetic programs of both the frog and otyugh breeding operations.
South of this node the Lost River falls down a mighty underground waterfall at least 600 feet tall. What lives beyond those falls is subject to rumours, speculation, and the nightmares of frogs.
(With thanks for ideas from Andrew Shields for the nagas and otyughs).