Michelle laid down atop the immobilized Marcus, running her hands over his lean muscles. "I can feel the rage and anger building inside you. The testosterone now flooding your body, raging through your blood. The hate you feel towards me, the burning seething loathing. And it makes me want your soul even more, but I see a seed in you, one I think will make even more fun." She raised her arm to her mouth, and gently bit down into her wrist. "You feel the anger of a demon, maybe I'll make you one as well. I already took your innocence, why not your humanity." Blood ran down her arm from the bite marks, holding her arm over Marcus' mouth, she allowed some to drip on his tongue. "Let the seed grow." She whispered into his ear, followed by a soft tease of her tongue. Then in an instant she was off him and out the window, and he was free.
But a heat was growing in him, a burning need, and the anger, so much anger. He tossed his head back with a howl of fury, his muscles having spasms all throughout his body. They began to swell, his lean runner's form packing on pound after pound of firm solid muscle, massive pecs swelling out from his chest, arms as thick as most men's legs, and legs even thicker. His skin began to deepen, first tanning then tinging red, a deep bloody crimson that covered his entire body.
The sex demon's blood in his body combined with his male form, making him into another like it, but of male sexuality. His balls swelled, like two balloons being slowly inflated. Bull like balls that hung down to his knees, a pair or massive grapefruits in a dark red scrotum. His penis swelled with blood, becoming fully erect and then going further. Lengthening inch by inch, growing ever wider as it did. Sticking out a foot in front of him, and not stopping. A foot and a half long, thick as a wine bottle, the massive cock throbbed, the demon blood now keeping his erection permanent, and ready, and needing.
The light hair of his chest began to thicken, a dark black pelt of fur that covered his pecs, only his deep crimson nipples peeking out from the forest of hair. The growth continued down his abs, engulfing the entire base of his massive demonic cock. The hair on his arms and legs thickened, even as a beard grew in on his face, short but thick. Even his face grew more masculine, his lantern jaw and thick brow giving him a look of pure male virility, even as giant curling horns grew out from his forehead, curling around ears becoming increasingly pointed. Fangs peeked out from under his lips as claws tipped his massive hands and feet. A thick tail snaked out from his hairy muscular ass, whipping behind him in a frenzy.
With a loud grunt his massive balls began to churn and his cock erupted in a flood of cum, covering the walls with a spunk that smelled faintly of brimstone. Expelling the last of his human vestiges with the orgasm, his new demonic blood coursed through him. And with one last growling gasp he passed out, sprawled on the floor amidst his own cum.