All New Encounters for your Rage of Demons Out of the Abyss Campaign
From the introduction:
Welcome back intrepid Underdark adventurers! Journey Through the Center of the Underdark 2 -The Darklake Strikes Back contains several more encounters meant to flesh out your days spent traversing the underdark. This time we're on the vast and varied waters of the Darklake, where the Kua Toa are Kua Toa and the fish are frightened.