A/N: A oneshot for an idea I was kind of beating around a little. Still haven't decided if I'm going to do anything with it yet. Takes place during 5x10, "Abandon All Hope". Without a doubt, the prettiest smut scene I have ever written. It kind of crept up on me and took me by surprise to be honest.

Disclaimer: I don't own Supernatural or Harry Potter.

Warnings: Smutty Slash! Castiel/Harry

Our Last Night On Earth

"There are two things I know for certain. One, Bert and Ernie are gay. Two, you are not gonna die a virgin."

So this was it then. Tomorrow we were off to kill the Devil. And truthfully? I couldn't think of better people to spend the End of the World with. Dean and Sam sat sharing beers at a table, looking at the picture we had all just taken with Bobby. Jo and Ellen were back to plying Castiel with shots and here was little, old me, Harry "The Good Witch" Potter, leaning on the back of the overstuffed armchair, nursing a drink of my own. This must be what family was like. Not that I would know, but if this was the real deal, I really had been missing out all of these years. Sure, I had Death and Tessa, but I had never really known family, not since they had plucked me from my relatives doorstep at the tender age of one. Reapers were never really a nurturing lot, with the exception of my mother henning Tessa, but Death had always shown me all of the attention he was capable of. I could remember tugging him away from "work" to play boardgames and to go out jumping in mud puddles, chasing frogs. The first time I had demanded to be taken on my first Reap with him at six and sobbing in his arms for hours afterward. It had been wonderful, but it had lacked the easy camaraderie, the To-Hell-And-Back friendship, that Team Free Will had. Friends. Something else I had never had before. To the Reapers, I was a commander. To Tessa, I was her charge to be cared for. And Death? I was his Master, his future eternal lover when I was finally ready to accept it. He was patient. After all, what else did Death have but time? Meanwhile, I had been freed to play the board before settling down, so to speak. To have other lovers.

Love. What did I know about such a thing?

I knew affection of course. It was what Death and I shared and to a different, though no lesser, degree, Tessa and I as well. It was what I felt when I looked at Jo and Ellen, Bobby and the Winchesters. But love? Perhaps...perhaps it was that burning, clenching sensation that permeated throughout my chest when my eyes met a certain pair of baby blues. Maybe. But how was I suppose to know? I'd never known love before. For all I knew this could just be indigestion. Yeah. That's what I kept telling myself, even as I snagged Castiel's last shot and tossed it back with a mischievous grin. He turned to look at me with a smile of his own and that feeling burst to life inside my chest cavity once again. This time, I was sure the burning feeling there wasn't from the whiskey. I turned away quickly to conceal the expression on my face from curious eyes. Jo hummed with amusement as I ducked into the fridge for another drink, hoping to cool the burning down to a bearable, less embarrassing degree. Maybe I should just retire for the evening. Everyone else seemed to be giving it some thought as well, the once almost bouncy air in the room tamed and sluggish. We would need to be at our best for the final confrontation tomorrow. Sighing, I snagged my last drink of the evening and headed towards the stairwell and my silent, impending room. Perhaps Tessa would pop in before I fell asleep and send a message back to Death for me. So distracted was I in my thoughts that the sound of footsteps behind me completely escaped my attention until my feet were already on the second step.

"Harry?"

Castiel's voice called to me softy from behind, as if he were afraid of engaging me. Nervous. It wasn't an emotion that featured often on the Angel's face which only made that change stand out all the more. The anxiety was endearing on him. It softened his borrowed features significantly.

"Yes?"

The smile he gave me was chagrined, shy and just short of incredulous.

"Dean tells me that it would be remiss of me to die a virgin." That would be one of that man whore's cardinal sins, wouldn't it? I fought down a grin and a roll of my eyes. Oh Dean. "Seeing as how tonight is our last night on Earth, I would very much like to spend it with you. If you would have me."

I had to admit, the thought wasn't an unpleasant one. Castiel's gravelly voice sent a thrill coursing through me, a heady desire. Having him close like this, alone and wanting me, brought that burning back with a vengeance. My chest practically throbbed with it, a strange fluttering taking residence in my belly. There was a fire inside me and I found that here in this small space, just he and I alone together, it wasn't such a strange, uncomfortable thing after all. He got a smile in return and I held out a hand for him to take gently.

"It would be my honor, Castiel."

"Truly, the honor is all mine, Master of Death." He whispered reverently, staring down at his lightly tanned hand resting my smaller, pale one. The look on his face was so awed that I couldn't help but laugh a little as I led him up the stairs. He looked at me as if I were the greatest treasure in all of the Heavens and Earth.

With Cas at my back, my room didn't seem nearly as lonely a place when we arrived. It seemed comical for a moment, me leaning against the closed door, warding the room with Silencing, Locking and one clever Anti-Reaper charm I had created and he standing in the center, eyes not flinching away for even a moment. I slipped my wand back into its holster at the small of my back and grinned.

"Do you know how to do this?" It was almost silly to ask.

"I am versed in the ways of human intimacy, between either gender." The amusement only broadened at his analytical language.

"Brilliant. Then, I suppose...you know these things usually begin with a kiss."

The seriousness in his face folded away like a curtain to reveal burning heat beneath. Its power was directed at me and me alone and that realization cause the smile to slide off of my face quickly. His hand in mine clenched, reminding me that we were still holding hands through it all. He was suddenly close, nearly too close for breath. Warm and sweet and wanting. A free hand came up to cup the side of my throat, thumb stroking the v of my collarbone in a way that felt strangely possessive, as a thirsting man hoarded water or the dragon guarded gold. It was a touch that belied how treasured and cherished I was to him. The soft intimacy left my knees weak and my heart aching within the confines of my chest. How could he have felt the same as I all this time and I had never known? The emotions were unfolding inside me, revealing themselves like flowers in the warm sun, bringing with them a profound realization that had the potential to shatter my life and all I knew of the world and my place in it.

"In all of my long centuries of life, never have I felt this way about anyone." His words came to me in a breath, a soft wind brimming with promise and mere, chaste centimeters away from my lips. If I had the ability to die, I would have thought my heart would surely give out then and there so hard was it pounding against my ribs. How I was able to draw a single breath was impossible to know.

"And...how do you feel?" I asked in small, fragile words, barely big enough for a mouse but somehow he deciphered them without shattering me to pieces. Doubtless before the dawn broke, he would have devastated and remade me several times over, but each time those calm, loving hands would rebuild me into something better. A creature of light and love and all for him. He was slowly making himself the sun around which I revolved and he wasn't even trying. His honesty in all things was a terrifying, glorious thing to behold. Castiel smiled down at me, seemingly as confused for a moment as I and pondering over the new revolution around him, inside him.

"I believe that I may love you, Harry Potter."

There was only a bare moment, the still calm before the storm, before his mouth was on mine. Lips and tongues said more than bare words could ever articulate.

When he kissed me, I cracked.

As tender hands lay me back against the cheap, musky cotton sheets, I shattered into the light of a thousand stars, miniscule pin pricks in the distance. An explosion of self and denial. A new sort of liberty was overtaking me, the freedom of letting go of gravity and fear. Hands memorized my every inch, traced Enochian sigils into slowly unveiling skin. I cried out but he only smiled down at me, swallowing the sounds down into himself and glutting himself on my every sound and stubborn silence.

When he at last moved within me, I didn't think that anything could ever remake me into something as wholly pure and perfect as he did in that moment. Castiel gave me a part of himself, a piece of that indomitable spirit that made up the being that he was.

For a terrifying moment, I feared. I feared giving that same piece of myself back to him, as if it would taint him, poison him. Wreck and ruin and Death followed at my heels all the days of my life. Could I risk letting him see that part of me, risk giving him some diseased piece of myself in turn? But really, there was mo choice in the matter. I had come to love this strange, amusing Angel over time. He had crept in past my defenses while I was none the wiser. What else could I do but relinquish myself to him? The victory had been won long before I ever noticed that he had invaded me, heart and soul.

Castiel hadn't been lying when he said he knew how intimacy between two men worked. With every shift and thrust, it felt as though his essence, that pure, scalding white energy were moving within me too, a tidal wave of euphoria and sensation. He broke me down to my most base pieces and turned me inside out like one would turn over and examine a priceless gem. Slowly, ever so tortuously slow, Castiel fitted me back together, each touch and stroke a return to self and a beautiful senility born of an unashamed, desperate love. When we toppled over the edge of the looking glass, we fell together, clutching bodies and spirits entwined as one.

For a long time, everything was black. The black one experiences when jumping into a deep, still body of water, breath held and eyes slammed shut. Soundless, sightless, endless. Had I died? Had my heart given out after all? Opening my eyes at last, it was to the sight of eternal blue. Some moments passed before I made the connection between the blue in my view and the loving eyes in Castiel's face. Slowly, my mind began to make the connections back to my body. An arm here, a leg there. The twitch of my fingers. I was coming back to life but not in the way of physical death. It felt as if before him, I had been a ghost. Lifeless and simply existing. Castiel had resurrected me from the dead, had breathed life into my cold body once more. His fingers were tracing those same sigils over my belly again and they left a pleasant tickle in their wake. Goosebumps raised up when a low chuckle breathed across my skin.

"If this is our last night on earth, Castiel, then I wish that every night could be the last."

The only answer I received was that adoring and adored quirk of his perfect lips.