Regulus felt his head drooping forward. His arm was weakening and he wasn't sure how much longer he was going to be able to defend himself. Voldemort was going to win this time. The younger Black hadn't done enough to weaken him. Maybe Kreacher hadn't been able to destroy the locket, therefore the Dark Lord was not yet mortal. Either way, it was almost over, and Regulus was going to have to face what he'd done.
Until he heard another voice. This one closer, louder than the whispers that had been plaguing him were.
Finding his strength, Regulus made it to his feet and whirled on Castiel. He was clearly unsteady on his feet, but his arm was steady as he leveled his wand at the other man.
"You," he hissed as if he actually recognized the other man. "You lead him to me! You turned me in!" Clearly this was the man who had told the Dark Lord that he was here. It was this man's fault that he was going to die. Regulus cast a quick glance back to the entrance where he had come from. What were the chances that he could make it?