"It's not possible."
Lust would like to scream in denial, tear the boy apart for daring to dash her hopes like this, but she cannot move.
"I'm sorry," the boy repeats. She wonders if he thinks this makes it any easier to accept.
"Perhaps I could change your hair or your eyes. Perhaps I could remove the Ouroboros tattoo from your skin. Maybe I could even make you an entirely new body, one that doesn't need the Red Stone, one that eats and drinks, sleeps, ages and dies like any human's." He sighs. "But in the end, you're still a creature from the Gate. Perhaps I could make your body human, but I can't do the same for your mind.
And there's no way I can give you a soul."
The Alchemist has spoken, Lust thinks bitterly. Doesn't work, sorry, no matter what you do or how hard you try you'll always be just a monster. Give it up, try a more attainable ambition next time. It's not the end of the world after all.
But it is.
"We were made to be human." Her voice is hoarse and whispering. "We were supposed to be human. The alchemists who created us meant us to be human."
The boy's brother stretches out a flesh-and-blood hand towards her, and at that moment she hates him, hates them all. Why does the boy gain all he wanted while her dreams are left shattered in the dust? Hasn't she suffered enough? Doesn't she deserve something for her pain?
Why does this 'soul', this ephemeral thing no one can measure, make such a difference?
She fingers the Ouroboros, the symbol that will always set her off from the rest of the world, and gets an idea.
"Damn you. Damn you all! We were made to be human. I was made to be human! And now you tell me it's not possible!" As her voice rises to a shout, she steps backward, slowly-slowly, so slowly the boy and his brother don't realise what she is doing.
"Well, then." She turns and starts running, quickly-quickly as the boy lunges forward to catch her. But she is a homunculus and faster than he can ever be so there is no way he can catch her and he falls onto his face in the dust as she leaps free.
Suicide as a homunculus is far too complicated to contemplate, but there is another way. As she runs, she reaches deep inside herself for that liquid, inhuman energy that is her life. And halfway through her next step—
and humans couldn't do this, have to drive themselves to the brink of death and then reach through that, have to pay a horrible price to even begin to get to this point, but she is not human—
the Gate opens up before her.
Ouroboros. Symbol of infinity, of cycles, returning to the beginning after the end.
She has come full circle.
She slows and looks back, at the boy and his brother staring at her in horror. The boy is trying to get up, probably wants to yank her back from the dark arms that are even now reaching out for her—
She sees his face, pleading silently with her not to do this. For a moment, she considers.
Then she remembers that damning pronouncement. "There is no way to make you human."
"If I cannot be human, then I will not be at all," she says and lets herself fall.
The darkness swallows her with nary a scream.