The stone basin loomed.
Regulus pulled himself up out of the boat. Kreacher stood on the stone landing and shivered, clinging onto Regulus's leg the moment his Master had come up beside him.
Regulus's wand glowed from his fist and he walked stiffly across the rocks. They were wet and slimy and slippery. His feet slid as he moved and he fell to his knees more than once as he climbed up the sloping pile of stone. He kept pausing frequently to lift Kreacher along.
Finally, Regulus put Kreacher on the pinnacle beside the basin's pedestal and then pulled himself up onto the stone, too.
He lay on the ground for a long moment, his cheek pressed to the rock, panting and feeling the cold stone on his feverishly-hot face. His arm was throbbing so hard that he imagined his heart there, for the beating felt more prominent in his bicep than it did in his chest by this point, and the sleeve of his shirt was bloody and sticking to his skin around the gash, the bandage having not been replaced after he opened the cavern door.
Finally, after what felt like hours of reminding himself how to breathe in and out, Regulus stood up, pushing himself up from the stone by the good hand, and inched his way closer until he was standing, staring down into the basin. He could see the locket laying at the bottom of the bowl, the chain curled about it, the liquid nightmare encasing it appeared as pure and as still as if it were encased in glass or ice. He knew better than to try at picking up the locket - it would not be possible until every drop of the nightmare had been consumed.
That was all there was left to do now, after all.
He'd come all the way through the cave, over the little lake in the darkness, and he'd climbed up here from the boat, and now --
Slowly, Regulus raised his arm up behind his head, and fingers undid the clasp at the back of the locket 'round his neck. The fake locket dropped into his palm and he stared at it for a moment. It felt heavy in the palm of his hand.. He wished he could take back the changes he'd made to the pendent for just a moment - just long enough to run his fingers over the letters BRAVE one last time... but they were already gone forever.
"Kreacher," Regulus said quietly.
Kreacher's ears were flat to his head already, his eyes as wide as ever could they be.
"Come here." Regulus lifted the elf up and set him on a stone that stood beside the pedestal that held the basin, where Kreacher could easily see into the bowl. "Do you see that?"
"The locket, Master?" Kreacher asked, looking where Regulus pointed.
"Yes, Kreacher," Regulus said. "When all of the potion in the bowl is gone... I need you to switch the lockets, remember? Take the real one out of the basin and replace it with this one." He held up the fake locket.
Kreacher peered at the locket in the bowl, then up at the fake one as it hung from Regulus's hand. Regulus held out the fake locket, giving it up, and Kreacher's hands closed around it.
It took all of his strength to let it go.
It felt even harder to breathe when he had. It was as though the air he was breathing in was barely even air anymore.
Regulus stepped even closer to the basin so that his abdomen pressed to the edge of the stone. There was a little hand bowl made of a mother-of-pearl oyster shell, which sat on the ledge of the basin. Regulus's hand shook as he lifted the empty bowl, turning it over in his palm, inspecting it carefully.
"Kreacher," he whispered.
"Master Regulus?"
"I'm going to drink this potion... so you can switch out the lockets... and I don't know what it will do to me..."
"Kreacher shall drink it, not Master!" Kreacher said quickly, "Not Master, no, no not Master! Kreacher will drink it! Kreacher will! Master will switch the lockets and Kreacher will --"
"No," Regulus's voice was firm, even as Kreacher begged and cried and pleaded, "Kreacher!" Regulus shouted over the din of the elf's tears, "I said no! I've already made up my mind that I'm the one that will drink it, so stop and listen to me."
Kreacher stopped begging and he listened.
Regulus thrust his wand into Kreacher's hand. "You may use this if you need to, if it helps you in anyway to - to do whatever needs to be done."
Kreacher held the wand in his little hands, and he stared at it, his big eyes filling with tears.
"I don't know what will happen to me when I drink it this time. I - I don't really remember what happened the first time. I don't know if it will kill me, or make me sick, or what it'll do but I need you to make me finish it, whatever it takes. Every last bit of this potion has to be drunk - by me, do you understand? Every last bit."
Kreacher looked up at Regulus. "Every last bit," he echoed.
"If you have to scoop it out and pour it into my mouth as I beg you to stop, you have to do it anyway, Kreacher."
Kreacher's tears began to fall from his eyes, streaming over his little cheeks.
"If I tell you I command you to stop and threaten to hurt you if you do not, you cannot stop even then... You must be loyal only to kindness, remember?... I don't care what I say or do or say is happening to me... You must make me finish the potion, Kreacher."
"Y-yes, Master R-Regulus."
"And then you'll have to change the lockets." Regulus said. "Do it immediately, as soon as the basin is empty. Don't hesitate, don't pause, don't waste any precious seconds because I don't know how long until the basin replenishes itself."
Kreacher's grip on the locket in his left fist and the wand in his right fist tightened.
"Once you have the real locket, you are to take it home to Grimmauld Place. If you can take me with you, then do it, but if not --" Regulus bit his lip.
Kreacher waited for him to finish the command. He looked up at Regulus expectantly. "...if not, Master?"
"Then I command you to leave me behind." Regulus's voice was firm.
"Oh, n-no Master, n-no, p-please..." Kreacher was sobbing full now, "Master R-Regulus... please..."
"The locket has to be destroyed, Kreacher. If I'm not there to do it, you have to destroy the locket. As quickly as possible," Regulus's voice was even and as flat as it had become back at Number 12, when they'd been standing in the Library discussing the journey.
"Y-yes, M-Master Regulus," Kreacher struggled to speak.
Regulus held onto the edge of the basin, the shell bowl poised over the clear liquid.
"An old family heirloom," Voldemort breathed proudly, "And so... so much more." He sounded excited at the thought of whatever more the locket was, and he reached down to stroke it gently with his long-nailed fingers and Regulus looked up at him to see his mouth had curved into an endearing smile, as though he were a proud parent looking upon the face of an infant child.
He might as well have been, Regulus thought.
"That which is contained in this locket is most precious. You might say that it means so much that it has become a part of me."
Regulus stared at the locket.
Regulus's jaw squared with determination.
He plunged the bowl into the potion and brought it up, his eyes searching what looked like the dark ceiling of the cave, but he was actually staring up into the place where the Dark Lord's face had loomed the last time he was there.
"A ta mort, Tom."
Regulus brought the shell to his mouth, and drank the first bowlful of the potion down in a single, long gulp.
Those were the last words that Regulus Black spoke.
The last words that ought to be remembered at least.
Kreacher heard more, of course, because Kreacher stayed as long as he could without breaking his promise to his Master. It took thirteen bowlfuls of cauchemar liquide to empty the basin, which replenished at an alarming rate so that even if the shell seemed to scrape the very last of the liquid, it was refilled again before the shell had even cleared the edge of the stone basin. It seemed to Kreacher that the basin would never empty completely, that he would stay here in this cave forever and ever, feeding Regulus bowl after bowl after bowl until the day he died.
Each bowl weakened Regulus more than the one before it.
The first three Regulus managed to take in himself, but Kreacher fed him ten of the bowlfuls while Regulus screamed and cried and he threatened to cut off Kreacher's head and add him to the placards in the hallway at Number 12 Grimmauld Place.
But that was all the potion talking - the venom of dementors coursing through his nervous system, through his veins - it was not Regulus.
And Kreacher knew that.
"Kreacher loves Master..." Kreacher whispered in reply.
The last bowl was the hardest. Kreacher held Regulus's head still as his whole body convulsed as though electrified, the shell trembling in his hand as he poured the liquid nightmare in, even as Regulus whimpered quietly, "No more, please, n-no more... I can't t-take any m-more mother... ple-e-eassse..."
When he saw the basin was empty, Kreacher said, "M-Master, y-you did it, you did it, Master! It's gone, it's all gone!"
Kreacher scrambled to climb up the stone step that made him even with the basin so he could better reach the locket, dropping the shell bowl as he did so and it fell from the edge of the rock where they lay, dropping onto the next one down... where it ricocheted and bounced to the next, skid across, hit the edge of the fourth, and broke into two pieces, part landing on the fifth and the other flying into the water with a tiny splash, so small at Kreacher barely noticed it at all.
But the water stirred...
He reached into the basin and took the real locket of Slytherin out of the basin and his heart pounded with a bit of hope. If this was it, if that was all there was to it, then he could easily swap the lockets now and grab onto Regulus's arm and they could disapparate home, home to Number 12, and once Regulus had slept off the potion's effects, they would play Gobstones again like Master promised and Kreacher would win him best of seven or nine or whatever number Regulus would want to play...
At the edge of the island, a hand reached out of the water, unnoticed by Kreacher, and grappled for the far side of the first stone of the island... and the inferi pulled itself from the water.
Kreacher paused to look at the fake locket, and hesitated putting it in the basin, knowing as he did what it was. It was Master's most precious object, and he gave the fake locket one last tight squeeze with his fingers, as though saying farewell to it. Kreacher lay it down gently, rather than dropping it in.
It was then that he noticed the sound.
It was like a low gurgling or a growling, like a person saying "ahhh" with their tongue stuck out of their mouth, but without having to pause to catch breath - just a singular, long note of expelling air... except it wasn't just on singular, there were many, and the number of them grew by the second and Kreacher grappled for his Master's wand, which was still aglow, and brandished it around to see what the sound was and he saw them coming up out of the water.
Bodies. Bodies of every shape, every size, every race... and they all had a blueish or greenish pallor to them, they were bloated and they smelled and they reached right over one another, climbed right over one another, without care or pause, their limbs pressing into each other's faces and throats, kicking the faces of others and pulling hair, pressing into one another's flesh, which some had more of than others. A few were barely wearing any flesh at all, but had rotted away to the point of being half-skeleton with garish teeth and eye sockets.
Kreacher froze in terror for several seconds as they crawled closer, the sound of their growing louder and louder as more and more came up from the water, as they seemed to multiply, growing, the rocks becoming covered with them, climbing closer, and from every angle so that when Kreacher spun to look behind him, they were coming up that way, too, and the island seemed to grow smaller, as though the tide were coming in, but it was not tide it was inferi - hundreds and hundreds of them, and the inky black water that surrounded the island bubbled and seemed to be in a state of boil, but in places where bubbles would normally be what cut the surface instead it was head tops and limbs, hands reaching up, and Kreacher let out a shriek.
The shriek echoed in the cavern and seemed to only make the inferi come faster, with more determination.
And in horror, Kreacher saw the first one grab hold of Regulus Black's ankle.
Kreacher scrambled, grabbing Regulus's wand with one hand and the locket with the other, rushing to get himself down from the rock beside the pedestal and he threw himself at Regulus, grabbing onto him. He used Regulus's wand like a sword, pointing it at the inferi, trying to make him let go of Regulus's body but the inferi wouldn't let go and Kreacher did not know any wizard spells, so he put down Regulus's wand and he clicked his fingers to do an elf charm, and a spark of light flashed against the inferius's fingers that would have stung quite badly, but the inferius had no feeling, so it did not slow him down. Another grabbed Regulus's arm and Kreacher shrieked again as yet another reached up and took Regulus's other leg by the knee.
"No, no!" Kreacher grabbed Regulus's shoulder and he realized he'd dropped the locket when he'd been stabbing with the wand and he reached back for the locket only to feel his grip on Regulus lost and he shrieked again and he threw himself to the edge of the stone and reached out, his fingers slipping over Regulus's shorn-off hair. If only Master had kept his usual mop of black curls -- if only --
"Master!" Kreacher wailed, "Master wake up, wake up, wake up!" But Regulus's body was limp and he was still whimpering and convulsing, and Kreacher shrieked and cried, and the inferius seemed to move faster and suddenly there was one grabbing onto Kreacher and Kreacher screamed, "MASTER!" but there was nothing to do - he couldn't reach and suddenly one of the inferi coming from the other direction knocked the wand and the wand rolled from the stone and into the water and the light of it filled the inky black water, throwing silhouettes and Kreacher could see thosuands of the inferi in the water...
"Master!"
And it was with horror that Kreacher realized he could not see Regulus for all the bodies in the mass below... they had swallowed him up.
And he had no choice -- he had a command.
He landed on the floor of the library in Number 12 Grimmauld Place, shaking, sobbing, curled into the tightest ball he'd ever been in in his life, clutching the real locket in his tiny elf fists.
Cadmus Peverell stared on in horror as the elf writhed and sobbed.
"Master... Master... Master..."