I did not get an impression that most demons are fallen humans, I thought that Jinu is one of the very few humans in the underworld. So the ending makes sense—it’s prevention of humanity extinction by the alien soul-eating demons.
I think the “all demons are fallen humans” interpretation is supported by one of Jinu’s lines: “That’s all demons do. Feel. Feel our shame, our misery. It’s how Gwi-Ma controls us”
I did not get an impression that most demons are fallen humans, I thought that Jinu is one of the very few humans in the underworld. So the ending makes sense—it’s prevention of humanity extinction by the alien soul-eating demons.
I think the “all demons are fallen humans” interpretation is supported by one of Jinu’s lines: “That’s all demons do. Feel. Feel our shame, our misery. It’s how Gwi-Ma controls us”