A/N: This is a work of fiction using characters that are trademarked by J.K. Rowling
Warning: Character Death
Regulus stood in the dark, wet cavern. He was standing on a small island, surrounded by bottomless waters. Barely noticeable steam rose from the water and the smell was unlike anything he had smelt before. The scent of mold and decay filled the room.
He looked down that the locket that was held tightly in his grasp. His hand shook, and tears pooled in his eyes. His vision blurred but his resolve was unshakable. He had committed atrocious crimes in his service of the Dark Lord and hoped his final act of rebellion would give his soul a small sliver of redemption.
Regulus looked up from the locket and saw his wrinkled house elf standing before him looked worried.
"Kreacher" he said and waved the elf closer.
"What can I be doing for Master Regulus?"
"Take this. Destroy it" he commanded and forced himself to hand over the locket.
"Yes, Master"
The elf popped away and Regulus heaved a sigh of relief. He reached into his pocket and pulled out the replica locket and placed it in the basin and watched as it sunk to the bottom.
His task done he prepared to meet his end. He walked to the edge of the island and watched as the inferi drew closer to the surface. One reached a hand out and gripped his ankle firmly. Regulus Black was dragged into the waters, never to be seen again, nobody knowing of his sacrifice.