Godless

Every living being knows what happens when a Godless falls in love with a human.
It's drilled into the minds of flirtatious teens and young adults by their worried parents.
If you truly do fall in love with one, your life is soon to end. That's how the myth goes, anyway.

Godless are said to have died out many a millennium ago. They no longer walk the Earth.

But they do walk the pockets of time inside Earth.