Creatures with free will and intelligence who evolved those capabilities (and speech) with the sole purpose of being better at hunting humans.

Creatures with free will and intelligence who eat humans. Not because they need to eat humans, mind, they’re perfectly fine eating other things, but because they genetically like to kill and eat humans.

Creatures with free will and intelligence who are biologically incapable of feeling emotions like empathy, sympathy, guilt, or remorse. Seriously, some have spent centuries trying to learn how to feel them, and have failed.

Creatures with free will and intelligence who’ll be the first to admit that they’re better described as savage deceitful beasts, and that it’d be foolish and suicidal to trust them as far as you can throw them.

And, that said, Frieren the character advocates (with extremely good evidence backed reason) for their genocide, but the book and the authors don’t seem to do the same thing.

There’s plenty of characters that try to get along with demons, or trust them (and often pay dearly for it), and plenty of chapters where we see the demons’ point of view and can’t fail but to somewhat empathize with them, even if they’d be unable to reciprocate.

At no point do the book or the authors try to make the readers hate demons. They make us fear them, sure, but mostly they make us feel empathy and pity for them.

Hell, the fourth fan favourite character is a demon (and what a fantastic character it is).

(Granted, the third are the mimics, but still.)