The Demon of the River (Patreon)

Local tales tell of an otter who managed to escape an execution he didn't deserve. During his escape he came across a peculiar cave with the remains of a demon within. He found  himself lured by its promises of power and revenge,  before being claimed by its essence.
The accounts say that the demon wanted to seize a new body for itself, but was somehow bested by the will of the otter, who was transformed into a powerful beast.  
Nowadays, they say that this being stalks the rivers and lakes seeking lost souls for his sanctuary.
I wonder if the tales are true...

A Commission piece for Erknuss on FA (@Wakka1993 on Twitter)