Voldemort, for all that he had pursued immortality with a single-minded determination for most of his life, wasn't entirely blind to the detrimental effects his efforts had had on his body. It did not take a genius to realize that the weak-minded had responded far more readily to the good looks and charming manners he'd been able to wield in his youth than they did to the snake-like features and high-pitched voice he had been cursed with after his resurrection, and the former Tom Riddle was nothing if not a genius.
Unfortunately, the only method Voldemort knew of that would repair the physical damage done by the creation of multiple horcruxes also involved reuniting the torn fragments of his soul with what was left of the original, and that was out of the question. It would defeat the purpose of creating the horcruxes to begin with, and invalidate fifty years' worth of hard work and Slytherin scheming.
He had thought to ask one of his most trusted servants to research the matter, once; he'd set young Regulus Black, even more brilliant and eager than sly Severus Snape, to look into the matter of souls, and discover how one might add to or multiply the volume of soul a wizard currently had. The lad had passed along several interesting facts before deciding he'd really rather not be a Death Eater after all, and terminated himself somehow before Voldemort could do it for him.
He knew better than to trust such an important task to a subordinate, now. Which was how he had come to be in the small town of Sunnydale, a Muggle settlement in the middle of a Dark Creature preserve on the American western coast, rather than sending one of his dwindling number of inner circle Death Eaters to investigate. His quest for the Elder Wand had reached a temporary sticking point, but as often happens, an unrelated yet significant clue to a separate mystery had cropped up in the middle of it: the name and last known location of the Vampire Angelus, who was, according to Regulus' original notes, the only known soulless being to have had a new, clean soul fitted to it long after its previous soul had escaped to a Muggle afterlife.
Breaking past the wards the American Aurors had set about the preserve without warning them of his presence had been the most difficult part of the trip. The area was under a series of layered, mild Muggle repelling and Confunding charms to urge nonmagical settlers to leave and not speak of what they had seen within the preserve, but there were no other area-effect spells in place; Voldemort simply cast a Point Me charm and strode boldly through the town in the direction his current wand indicated.
He came to a satisfied halt outside a door leading into a basement area that probably served as the Vampire's living quarters, and cast a Reducto at it with a smirk on his thin lips. A startled curse told him that the Vampire had been struck by splinters from the attack; his smirk widened as he stepped through the ruined portal and sent a Petrification Hex in the direction of the voice he'd heard.
The Vampire he'd been searching for, a large, pale, dark-haired being with defiant eyes, stiffened up like a board and collapsed at his feet. Voldemort struck him next with the Cruciatus Curse, waiting for the beastlike features and golden eyes of the creature's non-human nature to come forward, then struck out with Legilimency, intending to strip the answers to his questions directly from Angelus' brain.
Unfortunately, he had forgotten-- if ever he had learned in the first place-- that Vampires had a natural resistance to mental magic. Something struck back at him even as he sent a part of himself outward, something no less powerful for being almost entirely insubstantial. There was no time to react; a fiery sensation pierced him to the core, and then all sensation was lost in the indefinable pain of his soul-- what was left of it-- being ripped from his body. Again.
So much for dealing with demons, he thought vaguely, as he found himself once again as he'd been seven years before: less than the meanest ghost, a black, drifting mist.
"Winner and still champion," Angelus panted, sprawled loosely on the floor as the hexes on him relaxed.
And a fraction of Voldemort drifted back in the direction of Albania, cursing virulently as he went.