The Promised Neverland - Vol. 6 Ch. 51 - B06-32 - Part 1

[MangaDex]

 

[SpecialProjectY]

There's three sides of demons then:
1. Will eat whatever it goes, free or not.
2. Hunters only like Sung-Joo
3. "Vegetarian" who won't eat, regardless if raised or free like Musica.

If the kids will break The Promise, both 1 and 2 will go on hunts again in the demon side, most likely even over at human side as well.

It's the matter of superstition faith, since for now there's no actual benefit for demons to eat humans, they can clearly live normal life by eating anything other than human flesh.

There's no evidence in "gods" even exist in that reality, no actual magic have been seen yet, even that isn't proof of some deities.
Everything beyond comprehension might be also treated as magic or higher being too...

Meanwhile, kids arrived at the location and... nothing is there in plain sight.