Incubus
"Well well well, congratulations." An annoying voice pops into your mind in a foggy black world.
"Whaa... what happened?" You ask.
"Oh, nothing much. You just made a contract, but part of the contract involved you loosing your memories." The strange voice said. You still couldn't identify a speaker, or really even figure out which way was up in this strange world.
"Contract?" You ask.
"Oh yes, quite the interesting contract." The voice said. "It is like this. You wanted to be able to have sex with as many little girls as you could without consequence, so you signed away your soul to me."
"I... what?" You say as you try to get your bearings on the situation.
"Heee... hee... heeeee... So, I have decided to grant this wish. I have just finished re-shaping your soul. Your mind was unable to perceive things for a while as the transformation was going on. You have now become an incubus. A sex demon. You will have the powers to have all the sex you like with infinite sexual stamina and semen, and your semen will be especially potent. What's more, you will be able to manipulate the minds of others, especially women and girls. Although, since you are just starting out, you will not begin with the full powers of an incubus." The voice says, still not revealing it's form.
"There is a problem though." The voice said.
"Problem?" You ask.
"Oh yes, although it's really not that big of an issue. It's just that the vessel died while I was working on your soul. You see, it can't last very long without a soul after all. So, you will be needing a new vessel. It is probably for the best anyway. Since you have lost your memories, you will be needing new ones. Once you are occupying a new vessel, you will gain some new memories, and maybe even regain a few of your old memories. Of course, the memories of how sex works and your desire for it will be fully preserved. That was the aspect that attracted me to you, after all. I took extra special care to preserve that part." The voice says.
"Now, for an appropriate vessel..." voice says in a thoughtful tone. "Ah! This should do. A boy with a weak will. He should accept you. And, he seems to have a few sisters right in your preferred range. The mother is also single, and is primarily living off a trust-fund giving her income. People around her may not even consider it strange when her children start having orgies. This should give you quite a bit of cover as you start off building up your powers."
"I... am not sure I understand" You tell the voice.
"It is fine. You are effectively a blank soul after all. You will be able to figure more things out once you are in your new vessel and are able to try out your powers for a little bit. You ought to be able to get a handle on things after you've fucked one or two of your new sisters a few times."
You don't even know what to say to this voice anymore, but some part of your that must still remember a part of your old memories seems to like what he's proposing. Well, it doesn't sound like anything is moving in too alarming of a direction right now, so you will just let the owner of this mysterious voice do it's thing.
"Well then, let's get you in that new vessel, shall we? You will have to go to sleep for a little while again. The name of your vessel is William Silver. When you wake up, you will feel like you have always been William Silver, and like this as well as your previous life had all been a dream."
After saying this, the already black ream seems to fade into another foggy black, but more quiet, world.