"Edo-kun?" Al's tinny voice called into the dark room. "Ed? Are you in here?" His large metal hand pushed open the door to their room, spilling a shaft of light into the room. The full moon was framed in the window opposite, and the beds were neatly made. A chill went down Al's metal excuse for a spine- something wasn't right in here. Not at all. \
"Ed-brother?"
A leg became visible in the shadows as a figure stepped forward. It wore a black boot and black jeans, and judging by how short it was, must belong to Ed. The next thing visible were the eyes. They were large, and had a crazed look in them, as well as deep bags underneath. Another step brought to light his one real arm, dripping blood beneath the sleeve. For a moment Al was afraid it, too, was missing; but no, the sleeve bulged in the right places, it was just bloody.
"...ed? What happened? Were you attacked"
Ed began to laugh- not the boastful laugh of his youth nor the humerous laugh of a well-told joke, but a deeper laugh which held not mirth but something else- madness. When he spoke at last, his voice was deeper, and it chilled Al to the core of his armor.
"...the truth behind all truths"
"Wh..what? What are you talking about?" Al took a step backwards, his foot clanking against the floor. "Don't you see it? Father..." Another step forwards, and Al could see what his brother's left arm clutched tightly: his mechanical right arm. "...Ed.. your arm"
Ed threw the arm to the floor, where it clattered; then all was silence for a long time as the brothers looked at each other, long and hard. If Al needed to breathe, he'd be gasping for breath. What was wrong with his elder brother? Ed had always been the strong one, or almost always; not counting that time in the library, anyway. Finally, Ed broke the silence.
"...homunculous"
Al was confused. His mind flashed to Lust, Envy, Gluttony- but what could Ed be talking about now? Their father? Their enemies? What had the one to do with the other? "I.. I don't understand"
"...you asked me once if you were real. do you remember, Al"
He took a halfstep back. Was this what his brother meant to say? Taht he was manufactured? That Alphonse Elric had never existed? "...brother"
"...we're not. Neither of us. There were never any children, nor any mother. Homunculous"
"...what are you talking about! Of course you exist, look at you!" Al was starting to get really really scared. Had his brother lost his mind!
"..think about it. Humunculous, with memories implanted to make us think we existed. But we always were in these forms. Nothing before we arrived at Central was real"
"...Winry... what about winry!" "Another homunculous." Al took another few steps back. "..but they can't do alchemy... and we can"
"How hard would it be to program a sentient homunculous to blank out certain areas of data? Say, a particular figure's presence behind them, doing alchemy to simulate the homunculous having real power?" HE took another few steps closer, into the moonlight, shirtless, and lowered his voice. "...can you remember father's face"
"NOOOOOOOOOOOO!" screamed Al, dropping to his knees and clutching at his head. No, this couldn't be real, this couldn't be, he was real, he was! They had a real father!

Alphonse sat up in his bed with a clank. He looked around the small dim room, across some notes to the other bed. Ed sat up as well, yawning and rubbing his back.
"Al? what is it"
"...nothing, brother. Go back to sleep."