Regarding Freiren: Beyond Journey's End and the idea used there that the demons are a predator species that evolved speech in order to lie, and can never be trusted...
A lot of people have been quick on the draw with the take, "It is... how you say... le fascisme. C'est problematique."
Others have said, "Well it's fake, so it doesn't count."
I'd like to throw out an alternative. What if the author was socially bullied in their youth to off-the-charts levels?
You can get the idea of a creature that speaks solely to prey on humans from imagining a sapient human-hunting predator and adding a dash of evolution... but you can also get that idea by watching a particularly nasty human and then working backwards.