Too much spell, not enough soul

As the succubus lies nude and spread-eagled on your bed, letting you get a great view of her as she fingers her hairless pussy she moans and then sighs, "I have taken stock of your mind while your stock was shooting into my mouth. I was able to see your past and realized the odd situation we are in." She reaches over to your bedside end table to grab an empty soda bottle and shoves into her crevice, "You are not of a magical mind. You have no magical talent. Until you saw me you didn't even really believe anything arcane was real. So you are completely unaware of the spell you just cast. On total accident, just for shits and giggles, you have cast the most powerful spell in black magic. You have agreed to become an immortal, invulnerable, all-powerful, and irresistible being with the single purpose of corrupting the entire human race." She stands up, the bottle continuing to piston out of her vagina without her hands touching it, "and since I'm the demon here, it'll be lust. You have sold your soul in order to turn earth into one endless, gigantic porn flick."

You stand flabbergasted, not sure you understand. You've already agreed? You're going to become some sort of Hell-god? With speed you didn't think possible (especially with a large object stuffed between her legs) the demon ran in front of you and slapped you hard on the face. "The mistake you made however, was not having a strong or evil enough soul in the first place. Trying to channel into you anywhere near the energy I need to complete this ritual would cause your soul to explode into nothingness long before I come close to competing it. If I do not complete the deal though, my connection to Hell will dissipate and with it my power. My strength, my aura of seduction, and my ability to hide my form from mortals will all be shot to shit. What do you think your scientists or priests would do if they found a winged, fanged, purple skin girl with a forked tail?! What chances do you think a demon has in your world after being stripped of all their power?"

She grabbed your dick roughly, squeezing it hard enough that you feel as if you're going to cry, "And you are already condemned to Hell. You think this hurts? What I'm doing to you now is nothing compared to what they will do to you back home." Still holding onto you down below she grabs your face and hold it inches from her, all sexiness replaced by anger and rage, "you're already going to Hell, but as of now you'll be going as just another prick to **** for eternity after you die but even without my powers I'll still be immortal. Condemned to whatever tortures you humans can think of until the sun blows up your pathetic world and I am condemned to float through space eternally while Hell finally becomes the greatest orgy ever!"

She pulls the bottle out of her snatch and waves it in front of your face, your sore dick quickly returning to full mast as your nose catches the smell. Despite your best efforts you find yourself unable to keep yourself from licking the side of the bottle in front of you. "Luckily for us, I have a plan." She hands you the bottle to lick clean while she smiles at your pathetic desperation to taste her juices. "Like a penis stretches the walls of a virgins pussy, allowing it to take progressively bigger and bigger objects, so to can a soul and a person's evil be stretched by corrupting others. We'll need to be relatively quick about it but you need to corrupt others. You need to turn others with stronger souls into corrupting influences themselves. I can give you the power to do that. To maximize your corruption you'll need to cast a wide net, targets from different areas and just to maximize the effects we can put a trace of the other six deadly sins into their new attitudes.

Just to keep it simple though we'll start with a member of your family, corrupting family members always is a little stronger in the evil charts. Choose a family member and a secondary sin to we can imbibe them with. We can give your mother a touch of lustful greed and turn her into a happy, horny little hooker. Maybe your dad can became a bit envious of all the single men not chained to one woman every night and begin fucking around. Make your sister a vain, horny sexpot **** to become the best fuck on the planet? Just let me know who you wish to corrupt, and what you want their secondary sin to be? If you do it quickly enough, I'll let you eat my pussy."

Your mind swimming from the effects of the succubus' nectar gets you to quickly agree with her plan.