there are beings...only known as THEM that had a hand in our creation,so when adam and eve were created, IT was as well,to stop them from eating the forbidden fruit,but it was never allowed to touch them,due to their unnatural nature,but IT grew feelings for eve,so when eve ate the forbidden fruit,IT turned a blind eye...but the fruit currupted eve,turning her to a monster,IT was horrified,yet happy to finally touch and interact with their love,but then THEM bellowed from above

"IT u have failed,for ur punishment, u shall lose ur love, and forced to walk the earth,a restless entity of darkness"

with that,eve was dragged to the underworld...becoming the first demon in hell, and IT wonders this endless world,a dark spirit,enacting horrors to any human in its vacinity.

side note,while they're called IT,they're actual gender,while changeable,is mostly female)