Torokeru Kaikan Sokuochi Akuma

Torokeru Kaikan Sokuochi Akuma summary:

When trying to do his work correctly as a demon while the others are idling away in the demon world, Alfas goes to the human world and discovers a strong soul that seems delicious. But what will happen when the human he thought would beg for his life asks to have sex with him as his last wish? And what is this pleasure he's feeling!?