It will burn out his humanity, as poison burns the life from the blood.

Jonathan felt it constantly deep in his bones. He felt his human emotions drain out of him with each passing hour, year after year. All he wanted was for it to stop. He wanted to stop his empathy, compassion and love leaving his body or his mind but there was nothing he could do. Nothing he could do to stop the anger and passion for killing from filling is soul. He hated it. If it wasn't for his desperate need to live he would have ended the suffering himself, but he just couldn't bring himself to do it. He would get as far as holding blade to his heart but he never had the courage to drive it in.

By the time he was 17 and had met his little sister the desperate aching in his heart was almost gone. He was inch away from no longer caring that his human half way dying inside him. From no longer caring that the little piece of his mother's pure soul inside him was being burned alive. His sister was everything he wasn't able to be. She was so small, soft, caring and selfless. The human in him flared up for a moment before the demon growled inside him and pushed it back down, buried it under the self loathing and hatred. Clary represented everything Valentine had ever told him about his mother, she even looked just like the pictures of his mother as a girl. The small piece of humanity he had left wanted to know her, to have her know him and protect her like a brother should. But the demon in him just wanted her. He remembered his father's every warning about his sister and her friends.

He knew she loved Jace and the demon in him took pleasure in the fact that it hurt her to think Jace was her brother. Oh if she only knew.

His initial interest in his baby sister faded and was replaced by a fierce hatred for everything she was and everything she stood for.

His stronger half craved blood. It craved the destruction of human life. It wanted death, wanted to suck the life from the blood. Driving the blade into Jace's skin he had laughed at him for loving Clary. Laughed at him for feeling everything he wished he could feel. He hated the fact Jace's love for Clary made him stronger, not strong enough but stronger. And when Jace had plunged the knife into his heart his last conscious thought was that the image of Clary had probably given Jace the strength to do it.

He felt unimaginable pain as him soul floated away from his human body, a horrible burning, stabbing, twisting aching sort of pain. He felt himself being dragged down into a hellish pit filled with monsters, his own kind. A new body, much like his old one, was forming itself around his tortured shapeless mass and he knew he was no longer going to think a human thought again. All he would now know was pain and hunger for human life.