Kemonogami

Kemonogami (ケモノガミ), also known as Beast God, is the name of a type of lifeform in Digimon Survive. They are referred to as Digimon in other media.

Digimon Survive
The Kemonogami are a type of lifeform that exist in an alternate World to the Humans. In some places, Humans came to worship and/or fear them and as such would provide them with children as sacrifices in the hopes it would keep them safe.

In one small village, the locals created a shrine dedicated to worshipping the Kemonogami though eventually barred anyone from going near it due to many people going missing near it. Some referred to this as being "spirited away".

Some Humans would also find their way to the Kemonogami World in other ways, such as Momotsuka Takuma and his friends ending up there after walking through a tunnel on their historical studies extracurricular activities camp.