Snape glared at Dumbledore, his cheek twitching slightly, his raised voice filled with irrepressible hatred. "He clearly promised me! Lily would be safe! He clearly promised!"
"The Fidelius Charm!" Sirius seemed to realize something, and his expression turned deeply remorseful.
He clenched his fists and was about to strike his own head, but Remus Lupin stopped him.
Even so, his eyes reddened as he growled in boundless regret, "If it weren't for me! If I hadn't tried to be clever, James and Lily wouldn't have died!"
Harry felt his head buzzing. He stood there blankly, his face pale, as though even breathing had become difficult.
He had heard what happened next more than once from Sirius and Remus Lupin.
If they had not changed the Secret Keeper to Peter Pettigrew, and if Peter Pettigrew had not betrayed his closest friends and chosen to side with Voldemort, perhaps none of what followed would have happened.
Faced with the present atmosphere of regret, Voldemort naturally found it immensely pleasing.
He wanted to see everyone suffering—preferably not a single one left out!
Snape glanced at Sirius and gave a scornful laugh in agreement. "Yes! Black, you're an idiot!"
A self-mocking expression appeared on his face, and a nearly numb exhaustion showed in his eyes. He shrugged. "But I was an even bigger idiot! If not for me, the Dark Lord would never have known anything!"
"Anyway... it happened. Lily died. It couldn't be undone... I tried every method I could, but it couldn't be undone... It simply couldn't be undone!"
He shook his head lightly. His entire body seemed incredibly frail, and his eyes revealed an almost numb exhaustion.
"A whole soul can be matched with a new body, but a dispersed soul..." He gave a bleak laugh. "...cannot enter a new body!"