A few years ago, I had played this game where there was this guy who basically was the source of this certain energy that was, I think, needed for the survival of this angelic race or so, and he could give it to others via his semen. I remember it being a visual novel or so where there was also these large dick creatures that could turn people into, I suppose, 'Fallen Angels'? There was also an Hell which I think you could get to by being late out at night and agreeing to a fallen angel woman or so's offer.