Before investigating the pond, you need to find 4 fiends. They are hidden in objects on the island. You can hear their breath when you are near them. Right click them to set them back.
I would like a UI update for that like quest :- find this ?/4
Do I have to?
The final one is the pond right ?
There are 5 fiends. Once you find 4, the angel will tell you to find the last one, which is located in pond.