.:Author's Note:.

Summary: Leonardo struggles with losing control as he is faced with a terrifying new enemy even his brother's can't protect him from; Death.

Warnings: Copious amount of angst, major character death, mentions of violence, brotherly fluff, etc.

Disclaimer: TMNT is owned by Nickelodeon, Kevin Eastman, Peter Laird, Mirage Studios, etc. This is a fan-work and I own nothing.

...

Quicksilver

...

He could feel it, crawling through his veins, creeping under his skin like an insatiable itch. It burned him from the inside, quickened his pulse and caused his green skin to burst into sweat. He felt hot all over, and panic gripped his chest. Leo closed his eyes again and breathed deeply, concentrating on the flicker of candlelight behind his eyelids.

The patrol had been a disaster. They were on a later run, since Donatello had insisted they stay behind until he finished some kinks in the battle shell, which eventually was left at the lair anyway. Mikey spent the entire run complaining about an upset stomach because he'd eaten week-old pizza from his room. As soon as they caught sight of a band of purple dragons loitering near a dilapidated shop, Raph threw himself into battle without so much as an ear to Leo's cautions.

Leo shook his head. He couldn't throw the blame on the others. It was nothing new.

If anything, he should have been more attentive. Of course the Purple Dragons were a distraction. After the Shredder's demise, Leo had thought Hun and Karai would have separated ways, considering the general dissent between them. But it seemed their mutual hatred for the turtle brothers was far more compelling than their own interpersonal problems, and it had not taken long for them to back the turtles into the small shop and surround them with ninja and thugs.

Slowly, each of the brothers were separated. Their enemies were many, and a number of them were far more highly-trained than before. Karai had always seemed more tactical and intelligent than her supposed-father, but sometimes Leo wished she weren't. Eventually, she found him, yards away from his closest brother (Raph, kicking and screaming bloody murder as always), and challenged him.

It was always about honor between them. Leo could accept that. He should have known things would be different. Since Shredder's demise, Karai had grown more hateful. What had been a passive dislike stemming from her father's vendetta had molded into a dark vengeful animosity that broiled deep within her. She fought him to kill, not simply to maim or injure this time. Her black eyes were fierce, and her pressing attacks fiercer. Leo had been saddened then – Karai was an honorable, powerful warrior he had once respected, and had hoped would desist in her dark path once her hateful master had died. But it had only served to harden her heart and her purpose, and she fought him now with death in her eyes. He evaded her as he could, and then grew more offensive as the cries of his brothers, struggling against sheer exhaustion and overwhelming numbers, began to reach him.

When he finally disarmed her, she had looked, briefly, shocked and conflicted. A strange hesitance had come over her, until she finally unsheathed a hidden blade within her gauntlet and attacked him once more. Startled by her sudden counterattack, Leo had not been quick enough to entirely evade the knife which sliced through his plastron and nicked his skin. Hissing, Leo had turned to fight her once more when a shout from his brother gave him seconds to throw himself to the ground before an explosion rocked the abandoned building. In the chaos of screams and settling dust, Leo escaped with his brothers, but not before meeting Karai's dark eyes and her cruel smile.

He should have known then. Karai had lost all her honor after Shredder's death. Leo had driven her to desperation, and paid for it now.

Leo's abdomen clenched again, and a wave of nausea rolled over him. He clenched his hands, but the fear would not leave him. He was suffocating. The flickering flame mocked him, dancing with life and prosperity, candle still tall and proud.

Unfair.

It was unfair.

He was the leader. He was the bravest, the strongest. Fearless. Even though none of it was true, it still meant something.

He didn't want to die.

Leo screamed. He stomped on the candle, extinguishing it under his foot. He tore his bed apart, tossed his books and scrolls across the room, gathered the china tea set Splinter had brought him from Japan for his sixteenth birthday and shattered it against the walls. He punched at the concrete until his fists bled and screamed and screamed until his voice was choked by tears. He wasn't even aware that he was no long alone until he collapsed not on the ground but into a pair of warm arms. He struggled feebly, but the grip was tight and gently supported him to his knees. Raphael spoke to him, softly, but Leo couldn't make out the words through the sounds of his own sobs. He knew it was wrong though. Raphael should be screaming at him, or making some snarky comment in his thick accent, born of growing up on too many mafia films. Donatello shouldn't be hovering over his bloody knuckles and looking at him like he was going to break. Mikey shouldn't be standing at the doorway, terrified and trying to conceal his tears.

It was all so wrong.

Leo was moved into Donny's lab, on the spotlessly clean side that acted as their resident medical ward. He pretended to sleep, but the nausea wouldn't let him. Instead, he listened as Donatello and Leatherhead spoke in hushed whispers. He heard Stockman's name mentioned. Dimethylmercury was no natural poison, and it wasn't used in labs anymore. There is no antidote. They couldn't have known. The symptoms don't show for months.

Months.

The patrol had been four months ago. At most, Leo knew he would have about a month or two before he would be left in a vegetative coma until his body ate itself away. His body broke out into involuntary shudders and he fought against the sobs that threatened to tear from his throat.

If only he had noticed sooner. If he had let Donny test his blood, use it for some of his experiments, anything. Everything had been fine after the patrol. Raph had suffered a minor sprain of his wrist, and Mikey had a few bruised ribs. Leo's nick was quickly cleaned and patched by an efficient Donatello, and the injury had been nothing but a faint memory in the back of his mind. Now it burned him, hotter than the knife that had struck him.

At first, Leo was prone to irregular stomach pains. He had considered it a result of some spoiled milk or bad food, but the discomfort was brief and episodic, and it lasted for weeks. The aches made him nauseous, and eating became painful as his gums gradually became sore as well. He lost weight at an alarming rate, and Donatello had finally realized this was no simple case of stomach pains. He'd drawn Leo's blood and examined it for a few days. Leo had seen very little of his brother for a while, to his surprise and apprehension. Leatherhead had even showed up and locked himself in the lab with his brother for an entire day.

When Donatello finally approached Leo in the empty dojo, Leo had been immediately struck by the fragile state of his brother, who looked on the verge of a breakdown. He was trembling and mumbling and several shades of green too pale as he revealed what he found. Somehow, the great reveal had not been so terrifying then. Donny, at least, had known Leo's slim chances. Leonardo had simply thought this was another thing that simply could be fixed by a raid on Stockman's lab, or even from hacking into the federal medical database. Donatello even called Poison Control for more information and options, but everything was slim.

And Leo gradually began to realize that he truly was wasting away.

They had agreed not to tell Raphael and Michelangelo yet. Leo didn't know what this would mean for his family, but he wanted something to stay the same. Something to distract him from the throbbing scar, once insignificant, be it Mikey's bad jokes or Raph's sarcastic remarks. He told Splinter, simply because his father could see right through him. Splinter had been calm throughout the revelation, but when Leo had finally raised his eyes, the old rat's eyes brimmed with tears and a feeling of such sorrow had filled him then, for a father should never have to witness the death of his sons before him.

Leo continued to go on the patrols despite Donatello's warnings, mostly to keep up normalcy, partly to cling to it. His other brothers undoubtedly noticed the increasing bouts of dizziness and clumsiness, but aside from a few of Raph's teasing remarks, neither of them pried. Until, as they finished up a short bout against a few Dragon thugs, Leo had seized in the middle of a skirmish and collapsed on the ground. His vision had blacked out, and his hearing muffled, and he had been filled with such terror and helplessness then. When he finally came to, it had been to his brothers crouched around him, arguing and snapping at each other. When Leo tried to speak, Raphael turned from Donatello and met his gaze with wide eyes full of terror, and Leo knew that he knew. And that had filled him with more fear than his trembling limbs.

They drastically decreased the number of patrols after that night. Two of them would sometimes go out, if only to verify that the Dragons or Foot were not cooking up anything drastic. One would always stay back, usually Donatello. Mikey, all smiles and optimism, was reduced to a shell of horror and sleeplessness. Despite his deteriorating senses, Leo still heard his brother's distressed cries in his sleep, and saw him, from through the open crack of the lab door, tip-toeing out of his room to cry himself back to sleep in Donatello's arms. Raphael, his bitter, fierce brother, sometimes had to leave, and would patrol by himself, or with Casey. Leo knew Raph had been hit hard by his prognosis. Despite their constant disagreements, Raphael always seemed to have this notion of Leo being indestructible. Leo had survived a mobbing of foot and Shredder himself numerous times, after all. How could this invisible… thing, this split-second mistake, turn a fierce warrior into a helpless doll? Leo also knew that with his death, Raph would have to take up his mantle. Donatello was too gentle, and Mikey too careless. Raphael, his brashness tamed, had potential for greatness, and Leo knew it. Splinter knew it – he had talked with him before. But Raphael was terrified, either by the prospect of his brother's death or the responsibilities that would accompany them, or both, and so he sought refuge on the rooftops of New York City.

Things gradually became worse. The muscle seizures became more frequent, and his weight loss weakened him to the point of frailty. While Leo had tried to continue to be a part of their morning practice, he quickly began to realize that his blows were becoming too easy to sweep away, and every counter-blow was hesitant and soft, and accompanied by a look of such caution that it brewed in him a rage against his own helplessness. Instead, he simply took to sitting aside and instructing them, making comments and critical suggestions as he always did. He taught them to work as three, instead of four. They all fought awkward and unsteady, as if something were already missing. As time passed, even his evening katas eventually caused him pain and discomfort, and finally he abandoned them in favor of simple meditation.

But even that was taken from him as his concentration broke from the constant, aggravating pain. Donatello prescribed him a number of pain-killers, gradually increasing the dosage as the pain worsened, but nothing ever seemed to make it disappear. He would simply become numb and dizzy, and find himself confined to the med-room bed for hours on end. The alternative pain was almost worth the mobility, no matter how limited.

Leo soon became so uncoordinated that he often needed assistance getting around. It horrified and demeaned him at first, that he couldn't even move on his own, couldn't even walk to the bathroom or fill up a bowl of cereal without a pair of helping hands. His brothers were patient with him, though, Raph especially. Mikey made soft jokes, which Leo smiled at despite the obvious lack of humor in his brother's voice. Donatello monitored his blood weekly, as if convinced he could find a cure if he studied it hard enough.

If anything good came out of his deterioration, it was that his brothers spent more time with him. They spent numerous nights huddled on the couch under piled of blankets watching movies. Leo always got to choose, but he often let Mikey pick. He didn't tell them that he couldn't even see the screen half the time, that all he got was blurry flashes of color and a throbbing migraine. But the heat of his brother's skin and their soft laughter was enough to make him happy, so he said nothing.

He knew his way around the lair fairly well, and the constant assistance made it so that no-one suspected him at first, until Donatello asked him whether he preferred a peach or a pear. Because of his gums, he could only eat soft foods anymore, and April made sure to supply them with plenty of fresh soft fruits, jello, and canned soups.

"Peach," Leo said. There was a silence then, and with a sinking heart, Leo reached out and touched the banana in front of him.

"Since when?" Raph asked with barely concealed anger.

"A week or so," Leo answered, unsure. The days seemed to blur together now.

"Let's get you to the lab," Donatello offered. Leo wanted to snap at him that he had had enough of the med lab, enough of being poked and prodded and leeched of his blood when it clearly wasn't going to change anything. But instead he nodded.

"Can we watch Saving Private Ryan tonight?" he asked.

"Of course," Donatello said.

"I'll make popcorn, and there's cheesy lasagna for dinner tonight," Mikey added, voice an octave higher than normal.

Leo heard a chair grind against the floor, and someone walk away. Probably Raph. Leo hoped he would return that night for the movie.

He did.

Leo drew Donatello aside a few days later. He knew that, inevitably, he would likely find himself in a coma if a seizure or heart attack didn't get him first. Donatello shook when Leo told him, pleaded for him to euthanize him if it came to that. He couldn't bear to be an empty shell to haunt them, and would much prefer that they manage to move on instead.

That night, all his brothers huddled in the living room around him, all touching him in some degree. The television was off, but they talked instead. Leo told them of how proud he was, of Mikey for being so strong and brave, and to keep smiling forever; of Donatello for his sense of kindness and responsibility, and of his limitless ingenuity; and of Raphael for his untested loyalty and fire, of which Leo admitted he had always admired. He warned them of their few faults, and they laughed at his lecture, but Leo could hear the tears behind them.

He fell asleep that night, loved and loving, terrified, but calm.

And when the darkness took him, it was with quiet resolve that he accompanied it.

...

.:Author's Note:.

And that's it. Just a short 5-pager I wrote instead of studying for finals yesterday. No idea where the idea came from, but it was fun to write. There are all these fics about Leo quietly and responsibly accepting his own death (or almost-death) for the sake of his brothers/honor/some bullsh*t, but I wonder if he would really be so quiet about it. I mean, he's still a teenager, I figure he'd be as terrified as anyone else.

I may go back in and polish it/add scenes later. I didn't add much about April and Casey because I wanted to concentrate on the brothers, but maybe I'll add something later...

What did you think? Not enough development? Was something unclear? The characters too out-of-character? I struggled a lot with appropriately transitioning between past-perfect and simple-past. Was it confusing? Review and let me know!

Thanks for reading,

- Kerrigas