Isaac slowly got up off the cold stone floor, wobbling slightly and feeling sore. He winced as he stood up more, feeling the pain in his asshole from being aggressively fucked by the Incubus. He could still taste the demonic cum in his mouth from when he was coughing it up. For the first few seconds, it was a terrible taste in his mouth. But after a while, the taste began to change from a terrible one to a good tasting one.
Suddenly, a wave of pleasure washed over Isaac's body, causing him to fall to the ground on his hands and knees. He reached up to scratch his head, only to feel two small bumps growing in. As soon as he felt the horns, Isaac realized what was going on. The ring was loosing more power as he became more corrupt.
"Oh God, what do I do?!" Isaac cried. He could feel something extending from his tailbone, which he didn't dare look back at, as he knew what it was: a demon's tail. Not only was the ring loosing its power, but the Incubus's cum was changing him quickly.
He had to try to resist it. He tried to focus on his true goal: fixing his body and turning it back to normal. He didn't want to remain like this forever...did he? His question was so answered as he let out a moan, and wings began growing from his back, spreading more pleasure through his body. If all this pleasure was going to be given to him the way he was now, he knew what he wanted.
Isaac sat down, making sure not to sit on his tail, and with his transforming clawed hands, Isaac grabbed his cock and began fiercely jacking it off. He couldn't take all the pleasure anymore. He wanted to feel pleasure all throughout his body. He needed to be like this.
As he jacked off more, the demonic seed spread throughout his entire body, corrupting his cock and causing it to grow and transform into a cock similar to the Incubus'. Throwing back his head, Isaac moaned and let the last of his human seed out of his cock, which was promptly replaced by new demonic seed.
When Isaac finished, he heard someone behind him chuckling. Turning around, he saw the Incubus from a few minutes ago walking out of the Shadows.
"Well, looks like I was wrong about your mind being corrupted," he said. "So, I take it that you'd enjoy another round with me?"