Why would he want to?

Cade looked at Lilith for another second before he slowly brought his mouth to one of her dripping nipples. With the first suck, he nearly came again. The second had him hooked and the third left him completely addicted to the delicious taste. He threw away any inhibitions as he worked to drain Lilith's breast of its sweet nectar. Lilith moaned as he became more and more forceful and his cock rose to full strength again.

"Come on baby, whip that dick out. You know you want to fuck this cunt," she whispered to him, chipping away at what was left of his rational mind. Unable to deny the sex demon, Cade wasted no time wresting his hard penis free from his strained pants. Lilith saw the beginnings of hellfire in his eyes before he plunged his slick cock into her twat. They both groaned loudly and Cade eagerly began thrusting into her, his mind completely focused on sex with the succubus. Lilith was reeling with pleasure, her once empty cunt full of a fat dick once again. And to make things even better, Cade was already starting to transform into an incubus, bulging red veins crisscrossing his body, and his dick was growing to match, reaching deeper and deeper with every thrust. It wasn't long before it pushed at the perfect spot in her cunt and she came with a howl, her magnificent tits spraying jets of milk over her ravisher. Cade quickly captured one of her nipples again and nipped at it with new fangs, drawing out her pleasure further.

"Yeah, yeah, drink me, you hung bastard. I can't wait to see you fuck your daughter upstairs into a depraved slut like me. I wanna see that cute girl become a sexy hell whore!" Lilith cried, her tight pussy squeezing Cade's entire cock in waves, making his own orgasm boil.

"She'll get her turn," Cade said, his voice deepened to a demonic timbre. "I've got another whore to cum in first." His pace increased as he became increasingly muscular, pecs, abs, biceps, and every other muscle on his body gaining mass. He got taller, his average height extending upwards until he was over six feet tall. Slightly graying hair was rejuvenated, becoming pitch black and long as his skin darkened to the same crimson as Lilith's. His cock maxed out at nearly eleven inches of fuckmeat and his balls expanded to match, rolling with black, infectious cum. He wasted no time putting them to use, slamming himself into her one last time before jetting his corrupt jizz into her burning twat, letting out a guttural groan as his seed flowed into the succubus.

Lilith reveled in the feeling of his cum painting her walls, sensing Cade's new demonic urges to take and fuck. She had been right to target him first, he would make corrupting the rest of the family easy. She also knew now that in order to have her new strain of the virus take effect, the person would have to give in and accept it. She grinned and thrust herself on Cade's still cumming cock. It wasn't quite stealing souls, but it was close enough.

The new incubus' orgasm eventually ended, letting Lilith pull her well-used cunt off his still standing rod, which he immediately began to stroke, heedless of the combinations of cum that covered it. "Fuck yeah, demon pussy is the best. I bet teen demon pussy is even better. I can't wait to go fuck my little girl into a cum hungry slut," he grunted, his red dick throbbing harder at the thought.

Lilith smiled and scooped up a bit of cum that had escaped her still tight cunt, sucking it into her mouth. "Hmm, I promised, didn't I? You're the top dog here now. You can make any woman yours, make them squeal on your cock. No girl could resist that fucking rod. You can go fuck her right now if you want."