Hoyaukamui (ホヤウカムイ, Hoyaukamui) is a demon in the series.
A god of Ainu lore, it is the master of lakes. It appears a giant winged serpent with a pointed snout and slim head and tail. They have a terrible stench and if you merely approach it your skin can start to fester and you can burst into flames. Both Gods and humans must be wary of its stench. It hates the cold and thrives in warm temperatures.
"A snake god said to be the master of the lake in Ainu lore. It is also known as Sakusomoaipu, "He who is not to be spoken of in the summer". It has a thin head and tail, a fat body, wings on its back, a sharp nose, and red lining around the eyes and mouth. Its lake habitat gives off a foul smell; anyone who comes near will experience swelling of the body and hair loss."
—Devil Survivor 2 Compendium info
Hoyau Kamui appears as the strongest member of the Snake race. In Record Breaker, it is now second-strongest, with Kohryu taking its place as strongest.