I read this stories once on this website on a post apocalypse/apocalypse setting, with the FAE/FAIRY/elf invading earth, and with their magic Technology was banish.
The story follow this kid who just recently have his father kill cause the fae/fairy like to come to earth to hunt.
In a stroke of luck he actually kill one of the fae and the fae did a ritual of power and mind transferal BUT it backfire and the kid get the knowledge and power of the fae.
So he use it to enslave a newly fae female hunter.
blah blah the story end with the Kid realize that the fae was just a branch of human that forgotten it past and he banish them by using a magical staff power
yes it have sex