I need help finding a certain manga. This is what I can recall from it:
>super-humans being raised in a facility
>looks almost like a hospital with a clean white appearance with long halls
>essentially raised as cattle
>black haired protagonist
>finds out that they're being raised to be eaten by monsters
>tries to break out of the facility with a parter
It's not Neverland. The protagonist is in his late teens/adulthood.
The art is pretty graphic from what I recall, so I think it's a seinen manga.