Anna is corrupted

Anna decided it was better to obey. And after all, she really enjoyed it. She could feel her soul vanishing and burning, dispersed like cinder in the wind. She cried for a moment, a single hot tear falling along her cheeks. She thought about her loving father, about her boyfriend, and she apologized with them all.

Then it came: a wave of hot substance entering her mouth. She had never done a complete blowjob, but she was sure this wasn't the usual taste of cum. It was sweeter, denser, and simply too much to swallow it all.

-I said drink!-

Zack's hands once more were on her head, making her unable to move away. Her lips opened slightly, letting a dark substance drip from them. But it wasn't over yet. The stream of black cum was still erupting from Zack's dick, overwhelming the girl. She was about to vomit, but her stepbrother was continuing to **** her on top of his dick, causing her to swallow most of his cum. She could feel the hot substance reaching her stomach, and from there spreading in a web of darkness and evil inside her body. She felt... Somewhat stronger, it was incredible. Anna was feeling her eyes burn with the dark energy, beginning to glow in a purple unnatural light. She needed to fuck, to be filled once more, and her body barely obeyed to her commands. She jumped on her brother, quick and swift as a lioness, twisting her legs around his torso.

-Fuck me for real, bastard!

Zack didn't need an invitation. He grabbed Anna's butt with his hands, sustaining her weight and squeezing it passionately. He removed her pants, pushing them from behind and tearing them apart. He was now ready to fuck her cunt for real, but before he could move he felt Anna's nails pushing deep inside his flesh. He tried to scream, but this time it was she to silence him with a kiss. Zach could taste his own cum inside the girl's mouth, hot and sweat, the same taste he first felt when the dark tentacle entered into his stomach. He was in ecstasy, feeling a new power in his hands: the power to corrupt, to transform, to mold as he wished.

-Fuck me! What are you waiting, you idiot-

Anna had completely lost her mind. All she knew was that she wanted to be ripped apart by her brother's dick, and she would take what she wanted. She pushed Zack on the ground with a strong movement of her hips, making him fall on the cold floor of his room. Thanks to his improved instinct, Zach managed to not hit the floor with his head, but that violent act shocked him: the transformation had already begun to affect Anna, and there was no coming back now. She placed herself on top of him, making sure that his dick entered her cunt with all its raw power. She had only had sex with her boyfriend until that moment, and she begun to question if she would still enjoy it after that experience with Zack. She had never felt so alive, so strong. As she furiously twisted her hips around his cock, feeling it reaching deeper and deeper inside her, Anna could sense her body changing with the same rhythm of her crazed sex. Her vagina was expanding to accommodate for Zach's massive beast, as well as her hips overall. She could feel the black cum spreading inside her body, entering her cells and turning her in something more than human. She rolled her eyes back inside her head, as visions of lust overwhelmed her mind.

-Join me sister! Let the darkness corrupt you!-

It was a matter of seconds. Anna's skin became paler and paler, shining like the moon's surface in a pitch black sky. Soon, her perky boobs begun to be rocked by spasms of pleasure as her nipples erected and stretched out towards the outside. Her whole body was changing, transforming, shaped by her brother's darkest desires. Her boobs had grown quite a lot, enlarged to the size of two small melons. Zack pushed his chest up, Anna still on top of him, and begun to suck her big erect nipples like a small child. He could feel his sister's body changing, her nipples growing inside his mouth until they were as big as Becky's ones. Her red hair glowed and lengthened past her shoulders, looking like wild flames in a forest campfire while her lips enlarged and became the same colour of fresh blood.