Comments of chapter undefined of The Diamond Authority: The secret of Arkantia

Do you know what was the reason that humans were not supposed to be in THAT specific part of the forest? And why did Aoi give Elean a hand for her hunting since she was a siren meanwhile Elena is a human? In my opinion monsters and humans were not supposed to meet each other to avoid series of robbery in the area or is it because of the war that was lasting for sixteen years?