I can tell you where you will be, the day the world ends.
What would have happened if I hadn't been hungover?
You know the way it happens. One of the guys at work is getting married; you all go out for a quick beer to wish him luck (or commiserate, if you're Dave, in the middle of his third divorce: you think he'd have learned by now). A quick beer never lasts long: so you stay for a second, and everyone knows it's impossible to drink exactly two beers. It's either one, or all the way.
That night was all the way.
So that was my Thursday evening. There might have been a strip club; I can't remember. No-one got arrested, or into a fight, which you might call good news.
Friday morning I was running late for work; no surprise there. Good thing I decided not to shave; I might have lost half my nose. The mirror... rippled, and for a moment I thought I was still drunk: then it went dark, like the space between the stars. It took all the light from the room, then gave it back as points of light. I saw people, cities, countries: not like a camera zooming out, but all at once. You probably think I'm half-mad, but I saw it all, and I knew what it meant, but my God the headache it left when it stopped! Try remembering everything you've seen in a second, even with normal eyes, and there'll be some detail you half-saw or half-noticed or half-remembered, and my sight's like that. It's exactly like that, but there's layers to it, layers of what was and what is and what will be, and it all leads to the same moment. There are a million possible futures, and they all end on the same day.
I can tell you where I will be, the day the world ends.
I am there, an old man at the centre of it all, as things are collapsing. Debris crashes around me, to the left and right, but none strikes me. I'm speaking, frantically, bargaining; staring at the thing in my hand: a flat rectangle, three inches by five, and I hear a voice reply. I shake my head - there must be another way - but the voice just repeats its demand.
"Promise me your soul, and you can be young again."
Eventually, I agree. The mirror falls to the floor and shatters; the shards rise in the wind and swirl around me, splitting smaller and smaller until they are only points of light. They take all the darkness from the scene, then give it back as points of darkness.
I wake up, the same Friday morning, the worst hangover of my life, every time. If I'd been sober the night before, maybe I wouldn't have seen the mirror; maybe I wouldn't see the day the world ends.
I've tried changing it. I remember all the lives I've lived, trying to make the world last another day. I remember all the times I tried to run, to force myself to the other side of the world on the final day. I remember the time I took a shotgun, and blew my brains out; I woke up again the next morning, with the second-worst hangover. I looked in the mirror, felt the back of my skull (tender, like a bruise, but intact), and saw my face looking back at me. The me in the mirror spoke to me:
"You promised ME your soul."
I am in the mirror, and I am looking in the mirror, and I see everything and I am everything.
I am... Aether.