so...Lyra's been thinking...we have snowy mountains, fiery lava fields, wooded thickets, expansive plains, burning deserts, steamy jungles, a jade sea, a petrified forest, an infected urban metropolis, and one catacombs.
We need an underwater land o.o
Ya...that sounds weird...but hear me out. Imagine a long living underwater country of humans, who use powerful enchantments in order to live underwater cities. Something evil~~ is destroying the ocean, killing the fish, sinking ships, and all life in its path.
The normally secluded, peace loving and xenophoic race is now in dire need of aid! They reluctantly send ambassadors to the kingdoms of Tyria and Cantha pleading for help.
^^ so thats the setup.
Now imagine the visuals....your warrior, deep in the bottom of the ocean, a haze of blue and distortion (like permanent drunkeness). A magical enchantment given by your hosts allows you to breathe and survive in the deepest depths. Fish and Dolphin pets. Giant sea scorpion enemies. Sea dragons, anemone! Fire spells underwater!!!

The cities and outposts would be domed cities or air filled caves.
o.o so ya...im thinking of a very RPcentric expansion (non-standalone).