Not everything is underwater here, but a lot of it is! Most that dwell here can breath underwater or have ways around it. Nymfs, Water Elementals, Dark Elves, Giants, and Light Elves are live in the depths. You may be able to stay on land while here, but be careful of the creatures that will try to pull you under!
I don’t have the maps yet. 😦 Once I find them, I’ll be sure to post them! Now, where did I put them?