Disclaimer- I do not own Harry Potter in anyway. Nor did I come up with this theory.

Summary- Based on the popular theory that R. A. B is the one Regulus Black. Also based on an editorial on Mugglenet.

To Be Mortal

The cold pellets of rain stung his right hand; the only part of his body that was not covered with his cloak. Thunder and lightening were arriving more rapidly, coming more frequently than they had previously in the day. The pale flesh tightly gripping his wand looked ghostly in the darkness surrounding him.

"Lumos," he muttered, his wand now alight. Raising the lit wand slightly above his head, the figure peered in to the distance. The shadows that obscured his face hid a grimace.

"Should've known he'd make it difficult."

He sighed, shrugging off the soaked cloak that kept him only semi-dry from the rain. The moment it was off, his robes and flesh were soaked to the bone. Teeth now chattering and body shivering violently, Regulus raised the lit wand higher up again and narrowed his eyes to decipher his surroundings more thoroughly.

Pushing his jet-black hair back out of his face, Regulus clamped his wand between his still-chattering teeth and descended down the rocky, slippery cliff. His fingers groped at the slick ledges formed in the surface, slipping once or twice before he had a definite grip. Finally, he reached the bottom and turned around to face the raging sea.

The churning waves slapped angrily against the rocks protruding from the surface. Regulus grimaced as he looked towards his destination. He would have to swim from here…

Sucking in a deep breath, inhaling a few droplets of water as he did so, Regulus dove out, careful to avoid the sharp rocks. He resurfaced, immediately moving his arms in graceful, fluid strokes as his feet kicked, helping propel his body forward. He reached the dark slit in the rocky surface, and pulled himself out of the deep icy water and removed his wand from his mouth.

Out of breath, Regulus doubled over, his hands supporting himself on his knees although the water was still swirling up to his waist. He sucked in breath after breath, until he had regained the oxygen he needed. The trip in the water had exhausted him; he had to use more energy so he would not drown. His grey eyes flickered back where he came from, his black cloak blending in perfectly with the rocks.

"Accio Cloak," he said, catching the cloak as it came to him. He stood silently in the fissure of the cliff for a moment, quickly drying both his robes and cloak where it did not touch the water before moving deeper into the cave and through a dark tunnel that the fissure opened to.

He was still chilled, and he could smell the salt and seaweed more so now that he was out of the rain. Regulus forced himself to walk down the dark tunnel, his robes heavy and dragging behind him as he surged forward.

Still clutching tightly to the black polished wood of his wand, Regulus used the fingertips of his left hand to graze alongside the cave wall. He concentrated on finding any magical aura. His dark brow furrowed, as he felt no trace of magic.

He finally entered a cave, and paused. Holding his wand arm higher to illuminate the area more, Regulus glanced around the expanse of the cave. There were no forked tunnels to turn down to, no secret spots to slide in.

He grunted, turned his wand down to his robes and cloak and quickly dried them with a gush of hot air that emanated from its tip. He started pacing, growing very irritated that he could not figure out what to do next. Then abruptly, he stopped. Regulus felt an eerie tingling at the back of his neck. He slowly turned around, his eyes narrowing and brows furrowing in concentration as he pursed his lips. Reaching his left hand forward, he lightly grazed the wall with his fingertips. An electric shock coursed down his arm and spine simultaneously.

He was not triumphant, however. He knew that he should not celebrate early because he had not figured out a way to open the magically concealed entrance. Regulus tried every spell he could think of to open the sealed gate without any success. With a temper that rivaled his brother's, he picked up a stone from the damp cave floor and hurled it where the magical aura emanated from, letting out a loud, frustrated howl as he did so.

He sat against the wall, drawing his knees up to his chest and cradling his head in his hands. He growled, fingering the stones that sat beside him and pocketing one. Regulus tried to remember any spells that he had come across of in his young life that would help him reveal the entranceway to wherever the Dark Lord's horcrux was hidden.

Then it suddenly hit him like a hard slap in the face. He chuckled without humor, his head resting against the cave wall.

"Oh, my Lord, genius though you may be," he muttered with a ghost of a smile adorning his face, slowly getting up to his feet and bracing his hand on the wall for support, "but you lack originality."

He dug in his robes, walking towards where the aura was coming from and found a little knife that he used to cut potion ingredients with. He pressed the sharp blade hard against his left palm, and with a swift movement downwards he sliced open his hand. A hiss of pain escaped through his tightly clenched teeth, and he fisted his hand together, the warm blood oozing between the miniscule spaces between his fingers and running down his pale forearm.

"I believe," he told himself, "that I may have overdone this a little." And he reached up, slathering his bleeding palm against the cold, rough stone.

A silver arch had appeared in the wall, and then the entire rock disappeared, revealing blackness. Lips twitching in a grimace as he walked through, Regulus healed his hand before lighting up his wand. The light reflected several feet in front of him on the floor, and Regulus moved forward with a confused expression etched onto his face.

Peering down and moving into a squatting position, he lowered his wand to get a closer look.

He let out a short, strangled yell, hurriedly stifled by his blood-covered hand as he quickly scrambled backwards, his palm and knuckles becoming scraped against the rock floor.

Milky white eyes had stared back at him out of a decomposing face. He shuddered, taking in labored breaths as he tried to calm his racing heart and mind.

It had been an Inferi, a dead human body.

Regulus did not like corpses. He had heard adults in his life telling him that a stiff, dead, body would not be able to hurt him, but he knew better. Inferius can most definitely harm.

He swallowed deeply, slowly standing back up and raising his now extinguished wand.

"Lumos," he peered across to what appeared to be a lake, and spotted a faint, green glow. His lips twitched in dry humor.

"Well I suppose I have to get across the lake, now, don't I?" his eyes scanned the expanse of the shore. He walked along the ledge, feeling out for anything magical that might aid him.

"'Course I can't summon it," he murmured, "S'too easy. Wouldn't be able to apparate either. Bloody hell, why does he have to make things difficult?"

He felt a slight pull in his gut as he walked, and he stopped, taking a few steps back.

He reached out, finding the thing that made him feel the strange sensation in his gut. Something brushed against his fingertips, and feeling more triumphant now, he clamped his hand tightly around it and then tapped his fist with his wand. A chain appeared, disappearing into the vast darkness of the lake. He magicked the chain, and it began coiling itself up like a snake on the edge of the lake.

Ripples began to form, and suddenly a small, creaky little boat broke through the surface of the water. It made its way to the ledge, and taking a deep breath, Regulus climbed aboard it. Immediately it set off in the opposite direction, towards the eerie green glow.

The trip across the black water was uneventful. Regulus knew not to touch the water in any way, so he kept his hands clamped between his knees. He jarred forward slightly, the little boat having hit the ledge of a small, rocky little island.

He pulled himself out, eyeing the basin that stood all by its lonesome in the middle of the small rock surface. It was where the green glow had been coming from.

Taking, slow, deliberate steps towards it, Regulus peered over the basin. A glowing liquid substance filled the large bowl.

Regulus recognized it after a few moments, having taken Advanced Potions while at Hogwarts; he had also been tutored by Severus Snape under the Dark Lord's orders and had helped him brew potions before. But because this kind of potion was not in school potion books, he only guessed at what its effects would be.

Gripping the ledge of the basin tightly with both hands, Regulus contemplated.

"Kreacher," he called, and immediately a loud crack! echoed throughout the place and a wrinkly, filthy old house-elf appeared at Regulus's feet.

The house-elf bowed low so that it's squashed nose touched the ground. "Young Master called?"

"I am going to drink this potion, Kreacher, there is no other way to be rid of it. I am sure of that," Regulus stated, his grey eyes staring hard into the depths of the basin. "I am also fairly positive that I will not like it, that it will cause me great suffering, and that I will want to stop drinking it."

The house-elf looked confused and slightly wary. Regulus continued on.

"I order you, that no matter what I say—even if I demand it, that after I drink this potion, you will make sure I finish it," Regulus said in a firm tone, "You will obey no orders I lay upon you after my first sip of this vile thing, unless it is completely gone from the basin."

He looked at the elf for the first time. Kreacher looked positively alarmed.

"I may not be coherent enough when it's over, but whatever object that is at the bottom of this basin, I want you to take it and keep it safe until I ask for it. Do you understand, Kreacher?"

The elf trembled, tears welling up in his dull eyes. "Yes Master," he muttered, his head bowed.

With a flick of his wand, Regulus conjured a goblet out of thin air. He swallowed, taking a deep breath, before plunging it into the cauldron and filling it to its brim.

"Here's to, well, a good life," he managed one last feeble joke before he downed the potion in one gulp.

He nearly spat it out; it tasted vile and it burned his mouth, tongue, throat, and his teeth hurt as if they were sensitive to cold. He let out a strangled gasp as he took another goblet full.

The goblet dropped out of his fingers with a clatter.

"Oh, God," he choked, "I can't finish it--"

The goblet was shoved to his mouth before he could even finish and the potion spilled into his mouth. It felt like acid.

He let out a hoarse scream, remnants of the potion still in his mouth before he was forced to swallow.

Images plagued his mind's eye as another goblet full entered his mouth. He saw pleading eyes of every color, begging him for their life. Another mouthful was forced inside him and he started to hear voices.

"N-no-" he choked, his face heating up. "Pl-please I d-don't-"

"Master," Kreacher moaned beside him, but it sounded faint to Regulus, "Master, please forgive me, Master."

Regulus swallowed two more mouthfuls, shuddering as he did so. A woman was screaming in front of him, writhing on the ground. Such an innocent, pretty lady…

"No-no, I don't know, I don't know!" he wailed, "Please, please stop! I don't know anything! Oh God, help me!"

The hot liquid burned his mouth and the inside of his esophagus, some running down his chin and throat, but it felt icy on his skin.

"Please, I didn't mean to!" he moaned, rubbing his face and curling up into a ball on his side, "just let me go, let me go!"

"Almost done, Master."

"I'm sorry, I'm sorry, I'm sorry!" he wailed, "God, it hurts! Please stop, please, please stop! Just kill me please, I just want to die, just let me die!"

Images of tortured victims and dead, stiff corpses flashed before his mind's eye. Regrets that he had in his lifetime resurfaced, where he had buried the guilt so long ago.

He was sobbing, and a small hand was rubbing his back.

"It's finished, Master Regulus," Kreacher cried, great tears leaking from his dull grey eyes and leaving clean streaks down his grubby, squashed face. "Kreacher has the locket, Master."

He was moaning now, gripping the hair at his temples tightly. "'M so th-thirsty," he said with difficulty, his tongue feeling all too thick in his mouth. He pushed himself in to a sitting position, his entire body trembling violently.

"Master, Kreacher cannot summon water!" the house-elf cried in despair. Regulus shook his head, taking an object out of his pocket with fumbling fingers.

"L-later," he managed to gasp, his wand tapping the stone he carried and transfiguring it in to a locket. It did not look anything like Slytherin's locket, but it did not matter at the moment.

He dug in his robes one more time, searching for the little scrap of parchment that he had written on and waterproofed before coming to this place. It was a note, telling the Dark Lord that he had discovered his secret to immortality and that he would help whomever it was that was destined to defeat him.

Without any success, Regulus tried to place the folded parchment into the locket, but he was shaking too much. He looked at Kreacher, and the house-elf quickly rushed forward to do the task for him.

"Replace it in the basin," Regulus ordered faintly.

Kreacher did so, letting out an exclamation of surprise. "The potion is back, Master!"

Regulus did not reply, instead closing his eyes and letting out a ragged breath. "Take me out of this cave, Kreacher."

He felt a moment's disorientation before he opened his eyes and found himself in his old room at Grimmauld Place.

He braced himself against the wall, one hand out in front of him, ordering Kreacher to hand him the locket. The old elf dropped it into his outstretched palm, silent as he did so.

"Take me to an empty muggle warehouse," Regulus managed to form the words. With great difficulty, he told the elf the address of the one he had in mind, and Kreacher disapparated both of them out of his family home.

The warehouse was dark, the boxes creating shadows in every corner.

"Hide, Kreacher, do not come out," Regulus gritted out. He then placed the locket on an unoccupied space on the floor, and set to work on it.

He hurled every hex he could think of to destroy it, feeling his energy drain at every incantation he muttered. He could feel the protection on the horcrux weakening, but his strength was sapping too.

Then suddenly, the locket shuddered, letting out a blast of white light and Regulus was hurled off his feet, several boxes breaking his flight behind him. He gasped in pain, a trickle of blood dribbling down his chin as he rolled to his side. He felt nauseated at its metallic taste.

"Master!"

"Kreacher," Regulus called out, "Take the locket home, and don't come back."

"But Mas-"

"That's an order, Kreacher," Regulus forced out, his voice surprisingly steady. His chest pained him greatly, and he clutched at it with his hand.

With great agony, he raised himself up back in to a sitting position, glancing around the warehouse as he did so. Neither Kreacher nor the locket was in sight.

His breaths coming in wheezes now, Regulus stood up unsteadily on his feet, coughing up more blood as he did so. He thought he heard faint pops.

"Well, look what we have here," a smooth, silky voice spoke from the shadows. Regulus cracked a smile, his white teeth now stained red.

"Good-evening Lucius," Regulus replied, almost choking on the blood that came up his throat.

"Please, dear boy, don't speak," Lucius stepped out of the shadows, wearing his Death Eater garb, complete with the skeleton mask; four other figures stepped out of the shadows. "It looks like it's quite painful for you to do so."

"So, how'd you find me?" Regulus managed to straighten up, wiping the blood from his face with his hand. He was surprised that there was already dried blood on it from the healed cut on his palm. He grimaced.

Lucius chuckled dryly, "We've been searching for you for three days, Regulus. I'm surprised you lasted even that long."

"And why were you looking for me?" He coughed up more blood.

"Our Master thought that it was prudent to do so," Lucius replied, "Your loyalty seemed to be wavering. We are only being careful, you understand of course?"

"Of course," Regulus managed to say before he found himself choking on the blood that continued to ooze up his throat and out his lungs.

Another figure stepped forward. "What have you been doing to have put you in such a bloody state, darling cousin?" That was Bellatrix; Regulus would not mistake the female's voice in a million years.

"Oh, a little errand," He wheezed, his hand automatically clutching his chest. He shifted on his feet, trying to gain more balance as he swayed slightly.

"Well, looks like this will just make our job much more easier," Lucius drawled, raising his wand. Regulus knew he had no chance. He could barely stand upright as he swayed dangerously on his feet yet again.

He hacked again, this time almost a pint of blood escaped from his mouth, splattering the floor with a sickening slapping sound.

He chuckled dryly, "Our Master is a mortal."

Bellatrix stepped forward, her wand raised. "You will not be so insolent, Regulus! You always were a brat! You are going to die tonight! Don't you have any last, meaningful words?"

He laughed bitterly. "I always thought that you were suppose to see a white light before you die?" His speech was slurring, and he spat more blood out next to their feet. "There is no white light at the end of the tunnel," he said faintly, his eyes drooping as he stumbled, falling down to the floor. He was on all fours, and he was hacking painfully, his entire body convulsing.

"We will end your misery, cousin," Bellatrix's tone softened somewhat, but it was no comfort. "In some way you betrayed our Lord, and for that you deserve to die."

"I'm not sorry about what I did," Regulus looked up at her with great difficulty, his vision sliding in and out of focus. His grey eyes were duller than they were before, the light draining out of them.

He whispered, a small, sad smile forming on his lips, "But I do regret—"

He coughed weakly some more, the entire bottom half of his face and his torso was covered in the dark blood he was vomiting. His mouth formed the words that finished his sentence, but he was unable to make a sound to go with them.

Outside, a bright green light could be seen through the windows, illuminating the darkness of the old warehouse. Then all was back to black and silent.

Like it? Hate it? Either way, review! I'm glad to recieve constructive criticism.