Beneath the waves revisited

Artwork Originally for the beneath the waves challenge, I wanted to revisit the concepts and clean them up. This is were I'm at right now.
The realm of Ἀτλαντὶς νῆσος Governed by Taczull and Anza has remained hidden for centuries, now what remains are glimpses of what it used to be.
my characters are for the most part hunters and merchants that usually visit the sacred city to bargain and exchange their goods.
a lot of them travel alongside their creatures that keep them company and safety, while they provide them with plenty of food.
now because of human pollution their food sources are being affected.
there are a handfull of humans that know of this ecosystem existence but there is one in particular that is obsesed with the longevity this humanoids and creatures have, and is determined to decifer the reason to cure diseases in humans.
the name is Doctor Mary Vhauler.
when she finds the key to longevity, she will have to fight with all she has with the help of her underwater fellowmen to get back to the surface unharmed.