Pandalily but as Achilles and Patroclus. Lily saves the Wizarding world and Pandora has to watch her sacrifice herself in the process.
Pandora is a seer of some sort, she sees people's fate by touch, the first time it happened it was with her brother Evan. She tried to convince herself it wasn't true, that it was some sort of unrational fear of losing her only sibling and her other half. Evan always hugged her after the bad nightmares, reassuring her that he'll never leave her, that he'll be always there to protect her.
She never has any friends as she grows up because she can't bear the idea of the weight a stray touch could bring her. But through the years at Hogwarts, she makes a friend without even trying to. They sit in silence in the astronomy tower, close but never touching, he doesn't like people invading his space and she can't however much she'd like to hug him whenever she sees his eyes welling up on some days, they begin to talk and talk, she eventually tells him and he doesn't look at her like she is a liar or a freak. The next day he brings her a pair of white silk gloves to wear, and he clutches her hand tight as she cries.
The she gets paired with a girl with eyes the color of bright emeralds shining under the sunlight, her red flaming hair swaying with the wind as she reaches for one ingredient or another for their potion. She smiles at Pandora the first day they're assigned together, and she only looks once at the gloves on her hands. She knew she was a goner the first time she laid eyes on Lily, and she also knew the girl was a forbidden flower Pandora was never meant to pluck, only watching it from afar unless she wanted to unleash the wrath of the earth. But she comes to her, and love her Pandora does, and she does not have to have the help of a measly touch to know that she will reach for the garden's most possessed jewel.
Lily kisses her, and she sees it all. Not just their ephemeral and juvenile love but she sees green light painting the sky and a child's wails that never stop haunting her ears. And for once in her life she clings to the last shreds of mortal humanity she has, she clings to the naive hope that she can challenge the wheel of fate, that she could cut the strings playing with the people she loves. They are happy, oh so happy, and she thinks if she loves Lily enough, she would not leave her for someone else, for if she doesn't there will be no green or piercing wails. She just has to love her enough to will her to life.
It turns out she can't, as much as she wants to open her heart and let it bleed and become one with the salt in the sea, to fill oceans and let the excess flood the earth, she can't love someone enough to let them stay. She falls down to the ground and holds lily's hands in her own, she begs her not to go, not to join the good side and for once choose her, choose life.
Don't go to Troy she screams, but she watches her walk down the aile to intertwine her fringers with another, every step stealing her away to the other side where a grimm reaper stands.
At least she has Regulus, he holds her cloth covered hands as she weeps, as she becomes a shell of herself he tethers her to the earth. Evan is also there, he promised he would never leave. She has them, and it might be enough, they might not fill the Lily shaped hole in her heart but they will be the warmth surrounding it.
First it is her baby brother who breaks a promise.
Then it's a black haired boy whom she had never even known the warmth of his touch.
And then she looks up to the sky one night and she sees the green she had loved years ago morph ito the coldest and scariest thing she has ever felt.
One by one they fall to the ground and Pandora is left alone, her hands cold and her heart forever frozen.