Regulus plunged into the freezing water, the shock stealing what little breath he had left. He thrashed weakly, arms cutting through the dark in desperate, uneven motions as he tried to resurface. He barely made it before white, decaying hands caught hold of him. The ghastly creatures clawed at his robes, his skin, dragging him down with mindless force. The inferi feasted on him as they pulled him deeper. At first there was terror, sharp, blinding, but it didn’t last. It gave way to something heavier. Quieter. Determination, mixed with resignation. Regulus had known the chances of surviving this mission were slim. He had accepted it before he ever stepped into the cave. Someone had to do this. He was the only one who could. He had made too many poor decisions in his life, followed the wrong people, believed the wrong things. This felt like penance. Something earned. A small, traitorous part of him still hoped, faintly, that he might survive.

Water burned as it filled his lungs, the sensation distant compared to the pain of the inferi’s nails tearing into him, dragging him further into the depths. His struggles slowed. He stopped fighting. Instead, his mind drifted, away from the pain, away from the dark. He thought of Sirius. Of the two of them when they were younger, before everything went wrong. Laughter, shouting, sunlight. He wondered what his friends were doing now, if they were safe. The most satisfying thought of all was the Dark Lord’s fury when he discovered the betrayal. When he realized one of his precious horcruxes was gone. At least Regulus had done something right in the end. At least he had mattered. Maybe Sirius would be proud of him. For once.

The inferi continued to tear at his now-limp body. Then something changed. There was light in the water. Not the pale, sickly glow of the dead, but something else, soft, radiant, alive. It cut through the darkness like a blade. Regulus barely registered it, his vision blurring, his consciousness slipping. If he had been more aware, he might have noticed how the inferi recoiled, their claws loosening as the light grew brighter, how they backed away as if burned by it. A shape moved through the glow. Not an angel, not quite. Regulus had never been particularly religious, but in his haze, the thought crossed his mind anyway. Salvation, maybe. Or just a kinder end. The figure had long hair drifting freely in the water, skin illuminated by its own soft light. Below the waist, the body tapered into something else entirely, a powerful, scaled tail moving with ease through the lake. A siren.

Strong arms wrapped around him, careful and firm, pulling him away from the depths, away from the dead hands that reached but no longer touched. The ascent felt endless. The water grew lighter, colder, until suddenly Regulus was dragged from it entirely. He was laid out on the rock where he had been before, water pouring from his clothes, his chest barely rising. He didn’t wake. His body was heavy, unresponsive, completely spent. The siren remained for a moment, the glow dimming but not disappearing, watching him as he hovered on the edge of consciousness, gently caressing his face.