[Flyndaran]

I remember a setting I started but never finished about how all the sapient races were animals infused with elemental energies or bits of elemental spirits.

Like many such pseudo-races of D&D.
You could just go further with their entire souls being non-human/animal.

(Trolls were of fire, aggressive and always hungry; male dwarves were of earth and females of metal; mermaids of water; humans lightly of wood and elves heavily. We are grass, common and adaptable for good and ill.)