This is more of a Species Post.
Echoes are creatures born of pent-up, repressed emotion; they are "born" by the "parent" puking up a mess of pure existential matter, which quickly forms into the Echo itself.
The Echo takes on the general body shape of the parent; theoretically, a centaur would produce a centaur-shaped Echo.
Each Echo is born knowing several things: its birth name, its parent's name, the circumstances leading to its birth, and the Iquaquan (Echo) language.
They can reproduce normally amongst themselves or with other species.
There are four main varieties of them.