Nothing
Everything you did was done in vain. But those are the very words you died to avoid, aren't they? You died to avoid the shame of knowing you were a failure, that all you had done was for nothing. Your sacrifices, your despair, your blood spilled by the mouthfuls for the ungrateful cretins that smiled at your face and laughed at your back; you endured their mocking and insolence for some greater good that is impossible to obtain.
Don't pretend to look so troubled, you knew this pitiful truth before you boarded that weapon. You looked death in the face with the knowledge it was going to take you and you had done nothing worthwhile. You woke up to make a difference, and all you did was delay the inevitable. And such a delay was worth your sacrifice? You nod yes, I shake no; you frown, I smile.
Does a bump on the road stop the car from going to its destination? No. And so your sacrifice was that little bump, that slight turbulence, that temporarily paused the human race from destroying our kind and taking itself to hell.
Such a dirty look. Really, does it surprise you? Do you really think the humans will stay at peace with the Reploids for long? Ah, I've forgotten, you have no idea what it's like to be human. But I have an inkling of it.
Weil wasn't a special case, you know. It's human nature to strive for the sky, so to speak. Be it world domination or simple recognition from parents, but the human is wired to go above and beyond itself. So is the lesson of Adam and Eve—they rose above the pre-given roles and consequentially were exiled from heaven. Humans will forever seek what is above them, obtain it, and care little of the results.
Decent humans, you say? What of that tramp of yours, Ciel? Did she not do the same? She sought above her position as a simple scientist and reached for the ultimate prize: new energy. Raw, new energy the world so desperately needs. Do you honestly believe it never crossed her mind she held the fate of the world in her hands if she succeeded? She knew it, knew the possible implications of it… but she went for it. Will she use it to dominate the world? Perhaps not, but my point remains the same: a human will attempt to reach beyond its reach.
Where does this take me? The humans will make peace with Reploids. And then they will see what the Reploids have that they do not. Reploids will not die of old age, or even age at all. They will retain their youth, their vitality, regardless of time. No matter how hard a human works, a Reploid merely undergoes an hour procedure and never will they rot… but a human is a ticking time bomb, counting down to the second they will pass from the world. And the Reploid remains.
Eternally youthful, eternally beautiful; Reploids possess great strength and intelligence at birth, and are able to get stronger and smarter at a faster rate than a human. A Reploid will not fall ill of disease, nor die from a missing limb. Legs and arms are more readily replaced and accepted than if a human lost them. Reploids can travel to areas humans cannot survive…
Reploids are the next step, Zero. The humans will seek to erase the Reploids, by consuming the Reploids.
Perhaps your attempt to restore peace works for a while. But soon the humans will slowly chip away at what makes a Reploid a Reploid. Their rights, stripped, sweet cruelties masked with words like equality. You fought for the Reploids' place in a human world. You fought for the Reploids' place in human hearts. You died for that.
You died for the fact humans will never accept what isn't human. You died for the fact humans will seek to morph and mold the Reploids into what they deem is acceptable, manipulating our kind into thinking it is for the best. And soon, we will forever fade away. And humans will remain, conquering what they themselves create.
Depraved fleshy beasts, they will create victims to overtake! They will make their own enemies to go to war with! And then they go to war with each other.
You died for nothing. I died for nothing. X died for nothing.
And now, we shall become nothing.