Multifandom Oneshots

To Keep A Promise (Leviathan!Castiel imagine)

(A/N Can you guess who I'm obsessed with currently, by the way? Also, I'm trying out inserting characters into existing scenes. What do you think? Is there a scene in something you want me to try to put you in? Let me know!)

The lab/torture room/whatever the hell it was was too bright and too bloodstained. This was no place for him. He should be home, in the bunker, with you, he should be safe. He most certainly shouldn't be dying.

Cas's head was nestled against your shoulder. He was barely conscious, his skin pock-marked and melting, blood all over his suit and trenchcoat. Oh God, there was so much blood. You stroked your fingers through his matted and sweaty hair, trying to sooth him as much as you could while the boys worked frantically around you to get everything ready. The eclipse was almost on you, and they were still fetching things for the spell.

Oh God. The spell. You couldn't deal with this, you wanted so much to run, to cry, to scream at the universe, but you couldn't. He needed you, now more than ever.

"(Y/N)," Cas muttered weakly.

"I'm here, Flyboy, I'm right here."

"(Y/N), I wanted to say...I wanted to say that I am sorry. For everything I've done. I'm sorry for what I've done to Sam, and to Dean, and to you, especially to you. I need you to know that I did it with the best of intentions. I was trying to protect you. I needed you to know that before I..."

"Cas, don't you dare," you said, hand going to cup the less-damaged cheek as you smiled a watery smile down at him, "You're gonna be fine, you hear me? We'll get through this, just like we always do, okay?" He coughed painfully, and you helped him to sit up as much as he could to try and ease some of his pain. He seemed to be trying to say something else, but you shushed him, your free hand snaking down and taking one of his. He squeezed it, and you nearly sobbed at how weak his grip was. You squeezed back and rubbed your thumb over his knuckles. "You're not allowed to die yet, Flyboy, so don't even think about it. Promise me you'lll pull through this? I just got you back, Castiel. I can't...I won't lose you again, you hear me? Promise me you're going to live."

He stared at you for a long moment, and was so still that you'd just begun to fear the worst when he said, so quietly that only you could possibly hear him, "I promise..."

Then he smiled, and even though it looked so wrong on his broken face, even though it didn't reach the eyes you knew like the back of your hand, you smiled back.

In that moment, that last moment, you were both who you should be. Who you might never be again. Because you knew, when he left, you couldn't be the same. Something that beautiful, finding it and losing it the way you were right now, was enough to change everything you were down to your soul.

You would never forget this moment, and you would never forget him. You promised yourself silently, as you shared that last smile.

"Got it!" Dean came running in, Bobby at his heels, jar of blood in hand. You gestured wildly for him to start the symbol, and while he worked, you slowly helped Cas to his feet. Every groan and grunt of pain was like a knife through your heart. Finally, he was up, and the symbol was done, and time was running out.

"Bobby, do it now!" He started the incantation, and the symbol began to glow. Cas nearly fell, but both you and Dean rushed to pick him up again. "Get back," he whispered, and pushed the both of you away.

All you could do was watch as the wall began to fall apart, and just as Cas began to glow, he turned, with much effort, and said something you couldn't quite hear. And then he was nothing but light.

It was so bright that you had no choice but to cover your eyes. You didn't uncover them until you felt the wind cut out and heard a loud thump. Your eyes shot open and immediately found his prone form. At first, all you managed to squeak out was, stupidly, "I didn't hear him."

Then, with a strangled cry of "Castiel!" , you ran forward and slammed to your knees beside him, checking desperately for a pulse, for breath, for anything. But even as Dean and Bobby were grabbing your shoulders in an attempt to pull you up, even before Dean murmured a forlorn "Son of a bitch...", you knew it was too late. And you couldn't just leave him, and they knew, so they let you collapse over his chest, pretending that your sobs and screams weren't tearing them apart. Dean knelt beside you and rubbed your back slowly, trying in vain to sooth you, all the while staring at the fallen angel.

Suddenly he gripped your shoulder. "(Y/N). Look." He sounded shocked enough to stop you mid-sob, and it was in that moment of silence that miraculous sounds reached your ears.

First, a gasp. Then, a cough. Then, finally..."Well that was unpleasant."

You didn't know whether to punch him in his beautiful, stupid face or kiss him, so you settled for staring at the now breathing Castiel stupidly. Blue eyes blinked at you from a completely unmarked face, without so much as one-day stubble.

You cracked a fragile smile. Shakily, you replied, "Understatement of the year, Flyboy." His smile, that same familiar smile, on his whole face, broke you, and you hugged him tightly.

After a long moment, you let him go, and you and Dean helped him back to his feet. "Welcome back, kid," commented a flabbergasted Bobby, and Dean did nothing but laugh and pat his back. Cas looked around at all of you ashamedly. "I'm so sorry for what I did. But I will redeem myself to you, I promise."

"Shut up and come on, Cas, we can talk about redeeming you later. For now we need to find Sam." You shot Dean a look, but it wasn't serious, and you ended up grinning at each other.

"I mean it, Dean. I will."

"Cas, it's fine, you don't need to-"

"You need to run!" The change was so abrupt that even though Cas's actual push was weak, both you and Dean were knocked off your balance and stumbled a few steps away. Regaining your footing, you shouted, "What the hell, Cas? Why do we need to run?"

"They're so strong, (Y/N). They held on inside me." He was bent double, obviously in extreme pain. You moved forward, but he shouted "No!" again with such force that you froze.

"What are you talking about? What held on?" Dean asked, sounding slightly panicked.

"Leviathan!"

The one word was enough to make all three of you take an involuntary step back, eyes widening in horror as you watched Cas convulse, grunting, fighting.

Suddenly, he stopped and straightened, taking in a deep breath. And then he smiled. And you knew it wasn't Cas who was smiling at you. He stepped toward Dean and grabbed the front of his shirt.

"Cas?!" Dean asked fearfully. "Cas?" he repeated, still grinning, "Cas is...hmm, well, gone." And he threw Dean so forcefully, he was airborne all the way across the room, slamming down on and destroying a metal cart covered in glass bottles, which shattered in every direction.

Bobby ran up then, and the thing that Cas had become actually laughed, and slapped him so hard he was thrown aside as well, knocked unconscious to the ground.

You ran forward then, anger and hatred bubbling through you, but you pushed it back for one final try. "Cas, please, I know you can hear me!"

"Oh, no, doll," the thing grinned, gripping your arm painfully, making you scream, "Cas is gone, didn't you hear us?" It leaned in close, and you stared fearfully into those once-so-familiar eyes, now just empty pits. Breathing the words onto your face in a way that made your skin crawl, it said, "We run the show now."

It reeled you back and flung you, and there was an explosion of pain in your shoulder, then another in your back as you collided with the wall, breaking the tile, fragments of it running into your skin. You screamed through your teeth, then glared at it, struggling to stay awake.

It was smiling still, just smiling down at all of you. It tilted its head, and as you saw what looked like black ink flowing in veins up its neck and into its face, it said, "This is going to be so...much...fun..."