"Because he made a mistake during that ritual he had Pettigrew perform. Both he and that rat are paying for that mistake now."
"Explain please. I must know this time it's for good."
"He took my blood to restore his body. He thought doing so would give him the advantage over me. It didn't. As it turns out 'The Power He Knows Not' is basilisk venom mixed with phoenix tears. For almost anyone but myself, my blood is toxic now and has been since the end of my second year when I took a venom filled tooth to the forearm. Fawkes cried into the wound when I pulled the tooth free so I could have a weapon to attack the diary with. Basilisk are equal opportunity killers. They don't care who you are or how great you think you are or should be. They will kill you simply because to them you are food."
"For him, my blood is doubly toxic because of the phoenix tears it contains. So really you could say my blood is a brand new version of poison for which there is no antidote. Phoenix really don't like dark magic. They attack it whenever they come into contact with it. Which is exactly what is happening to him now. While the basilisk venom in my blood attacks his organs, the phoenix tears are attacking his magic. For me, the tears heal whatever the venom tries to destroy because my magic isn't dark. But for him, the tears are more concerned with the darkness of his magic. So they aren't healing him as the venom destroys his organs and blood cells. Nor will trying to get a new source of blood do him any good since my blood has already infiltrated all his organs and his new body will simply convert any new blood he gets to my blood's composition."
"And since he used both his blood and magic to create that silver hand for Pettigrew, the rat is also suffering. If he isn't already dead, that is. Of course it could be he simply lost his hand and his blood is now as toxic as my own. I doubt it though since somehow I do believe his magic is very dark just as his Master's is. And since the Ministry has already declared Pettigrew as a dead man, there will be no one looking for him or any the wiser as to his passing. In fact, the only people who'll even know are those who already know he helped your Dark Lord return. I'm almost certain none of them will say a word. Whether he dies or not."
Severus snorted even as he nodded his head. "What about the method he used to stay here as a whisp? Albus said he'd made anchors to keep his spirit tied here. More than one of them."
"Albus lied. He only had the diary because after he made it, it took him weeks to recover his strength and he didn't like that. He didn't like being vulnerable and needing to hide from even his own followers during that time frame. He figured the more of them he made, the longer he would need for recovery per item. So he never made another after he created the diary."
"Then why didn't he vanish after you destroyed the diary?"
"Because a portion of his spirit wasn't in the diary and when I destroyed the book, that portion was more than likely inhabiting another corporeal being. Animal or human, that body would hold that portion here when the portion in the diary fled. I suspect that the unicorn blood he drank while possessing Quirrel gave him enough stability in his borrowed host that he didn't need more than one host after I sent the diary soul onwards. It was just under two years later when I was kidnaped from here for that ritual remember."
"When he underwent that ritual, he was in the form of a young baby A baby no more than a year and a half old if it was that old. I suspect he had taken possession of the mother while she was pregnant and switched to the baby just before it was born. Either that or she got pregnant while he was in possession of her which is just gross and something I definitely don't want to think about. Dark Lord possessed woman having sex with a man. Ewww." He shuddered. Severus' lips twitched though he too felt a churning of nausea in his stomach.