Nagini was twining herself about Draco's legs. Draco froze in fear. I was well known that Nagini was a poisonous snake. Had the Dark Lord sent her to kill him?
Well, Draco thought, at least it will all be over soon. One little bite is all.
But then he realized that this way of dying would be much longer, more drawn out, more painful, than Avada Kedavra. And he began to shake.
Suddenly the snake began to lengthen and morph. Soon, there was no longer a snake sitting on top of him, but a woman. She appeared young in form, but...there was something about her eyes.
"Relax, little boy," she said in a low hiss. "I'm not going to hurt you"
The Dark Lord stood alone in the clearing, sifting through his thoughts. He refused to use a Pensieve on principle; the idea that there was even a remote chance that someone could access his thoughts did not work for him.
He was thinking of Nagini. The thought of her had sustained him when he was ripped from his body; his mind had dwelled on her, and she had found him.
Many thought that he had met Nagini when in the wilds of Albania, but they were wrong; even his closest Death Eaters did not know how long she had been his companion, for when he'd first begun his quest for dominion, so many years ago, he had kept Nagini, even in her snake form, a secret.
When he had met with Dumbledore for that teaching position, it was not Dumbledore's knowledge of the name his minions that had discomfited him; no, what had concerned him was the horrible questions that this raised: if the old man knew of the Death Eaters, what else did he know about? Did he know of Nagini, the one ace that the Dark Lord would always have up his sleeve?
After careful study, however, he'd become fairly certain that Dumbledore did not know of Nagini or when they'd met.
That day was still fresh in Voldemort's mind:
It was soon after Dumbledore had left the orphanage, leaving a young Tom Riddle gasping with new knowledge. His mind boggled; he had known he'd had power, known he was special, but now that he knew the true nature of his magic, he could use his powers to their full extent.
As per Dumbledore's instructions, he visited Diagon Alley, and spent hours poring over the shelves in Flourish and Blotts. He purchased a wand with the money he'd been given out of the Hogwarts fund, and enjoyed tormenting the other children in relative ease with its help.
But he wanted to do something big and unforgettable, even back then. He hadn't formed his plans to be Lord Voldemort yet, and back then he did not have much patience to speak of. So he decided to summon a daemon lord to do his bidding.
Interestingly, it was in a book from a Muggle library that he found the method. It needed to be refined, of course, for it had been written by a Muggle scholar and philosopher, not by a wizard, but the principles were there and were accurate.
He checked out the dusty tome and brought it back to his room under his cloak. Luckily the librarian no longer saw too well and didn't question the title, but Tom knew Mrs. Cole would if she saw it, so he was careful.
That night, he snuck into the weedy little yard behind the orphanage to do the summoning.
Tom had memorized the spell, and now spoke it, wand out, feeling more powerful with each word.
The earth cracked open beneath his feet, and a column of flame and spitting sparks shot up. From it emerged the daemon lord.
His skin was black and marked with gashes, the sort that never heal. They oozed thick red blood.
He stood on muscly legs like those of an ass, and was as tall as the orphanage, with huge leathery wings and jet black horns. Poisonous snakes twined themselves around the creature's scaly, grotesque arms. He had ridges like a dragon and a long, whipping tail.
Young Tom said his binding spell as the demon roared, and pointed his wand at it viciously. To his astonishment and horror, the spell bounced off the creature's hide to hit the side of the building behind Tom, showering him with broken concrete.
They daemon's eyes narrowed as it observed Tom. "You think you could possibly control me?" He laughed, a terrible sound. "I am the Daemon Lord Death-Thief, and I bow to no one"
The shadowy monster approached Tom menacingly. "Now that I am free," he growled, "I can dominate the entire world. And for your arrogance, little wizard, you will be the first victim of my new regime"
Fire flew from the demon's mouth. Tom dodged it, but only just, and he was smart enough to know that it was only a matter of time before the creature destroyed him. And he'd never even gotten a chance to go to Hogwarts.
The daemon lord's huge clawed foot came down on top of him. He screamed in pain.
Tom looked up into the demon's shadowy face, determined to die with dignity, and saw one of the snakes uncoiling itself from the demon's arm. It fell to the ground and began to grow rapidly.
Just as Tom was thinking that this was all he needed, the demon's minion to be growing, he saw that it had become a woman--or, at least, he supposed, something resembling a woman.
The woman launched herself at the demon, bathed in silver light. The light flashed brighter than anything Tom had ever seen, and he was momentarily blinded; when his vision cleared, the deamon lord had vanished, the split in the ground was gone, the wall of the orphanage was repaired, even the pain he'd felt just moments before had subsided. All that remained of the incident was the woman, standing above him and holding out a hand to help him up.
"Wha--who are you?" Tom asked, not taking the offered hand.
"I am Nagini"
Tom picked himself up, his eyes never leaving her. "What did you just do? Where's the daemon"
"He will not bother you again"
She was obviously selective about the questions she would answer. Tom knew that game.
"Will Hogwarts expel me"
"They'll never know"
Tom eyed her suspiciously. "Why are you helping me"
"Why not"
Tom could not think of a satisfactory reason why not. However, he also couldn't think of a satisfactory reason why. He remained puzzled and wary.
Nagini shrunk back into a snake at that point, and he distinctly heard her say, from that form, "You can understand me"
It wasn't a question.
She remained with him, and it didn't surprise the other children that he'd taken a snake for his pet. Tom remained suspicious of Nagini at first, but she helped him on many occasions, both in and out of school, and soon became his most trusted confidante. In fact, she was probably the only creature he had ever trusted.