Some supernatural entertainment (Demon Male reader X Highschool DxD)

There was a reason the three factions called the realm of devils and fallen angels the underworld, and that's because there is an actual hell, where the dammed souls of humans go when they die, becoming demons with unnatural powers. Now usually it's impossible for demons to escape hell because of seals made over the realm by the biblical god back before his mysterious demise, but time has passed and their starting to slither through the cracks, lets follow one shall we?