For the Edwin Week 2016 prompt, "promises." Cross-posted on tumblr and AO3.

Did she know, at the time, how much effort it would take to keep that promise?

I'll only cry tears of joy.

And on his side: I promise that those will be the only ones you need.

Did she know he would rip years off the end of his own life to keep that promise? Did he not realize telling her would compromise hers?

"You did what?"

Her fingers spasm toward the raw edges of the scar he shows her. She thinks maybe if she touches it, she can heal it with sheer force of will—that maybe she can send some of her own life into him.

But she pulls her hand away. Maybe it never moved in the first place.

"Yeah, I had no idea it would actually work like that. Pretty ridiculous, huh?" he asks, distantly regarding the angry red and purple blistering his skin like the scar doesn't even belong to him.

She can't make a sound at first. He's so casual; after all that mess, he chalks it up to luck and determination. Can she blame him? Even if the first has been hard to come by, he's never lacked the second.

"Yeah. Ridiculous."

When she finally manages to say it, her voice is high and wrong. Why is everything in her chest so tight? He came back, didn't he? And alchemy is so tricky—maybe it means nothing. A few years here, a few there. No one can measure the hours down to his own death. It's foolish even to try.

"Winry, come on. You see stuff worse than this every day. Stop looking so nauseated."

She doesn't feel anything abnormal showing on her face. Then again, she doesn't feel altogether that much. What, exactly, is the proper reaction when your ex-alchemist-not-quite-boyfriend slides out of his shirt and tells you he somehow managed to use himself as a philosopher's stone?

Well, maybe it didn't happen exactly like that. There was a bit of preamble before the shirt came off. But she'd say it's still a tough situation to correctly react to. As a result, the first thing she thinks to say comes out of her mouth:

"So…how much did you lose?"

She didn't mean to ask it that way. But now she has.

He looks down at his hands, one still much whiter and softer than the other.

"Well, since no one has ever done this, exactly, I'm not sure. It could be a couple years, or ten. It's too much to hope that it took less than a year away."

A couple years. Or ten. Her lips form an "oh," but it doesn't come out of her mouth.

He slips the shirt over his head again, pulling it down over the patch of deep, bruise-colored scar tissue that's bigger than his own hand. He's had time to get used to this truth about alchemy, and what it demands, so he's not bothered by the sacrifice anymore. Or at least, he doesn't seem to be.

"It was either that, or bleed to death at the bottom of that mine shaft."

She feels acid rise in her throat at how nonchalant his voice is.

"Don't do that, Ed."

He freezes with his hands still holding the hem of his shirt.

"Winry—?"

"Don't talk about your life like that. I don't care what you had to do to heal yourself—that's different. I'm glad it worked. But don't—don't…"

The air between her lips hisses out in a half-sob, and she's frustrated at the sudden tide of pain and anger that roils in her stomach. Her fingernails dig into the roughness of the workbench, and she almost relishes the bite of the splinters. It's only right, after hearing about his pain.

It's a big scar. What kind of wound could leave such a thing without taking a life?

She can't meet his eyes again, she doesn't want to see whatever is there, whether it's resignation, or regret, or anger, or pity. Especially not pity. He takes a deep breath, and she waits for him to chastise her.

"Sorry."

She stares down at her fingers, uncomprehending.

"What?"

"I'm sorry. I don't want to make it any harder to keep your promise."

She looks up at him. His confident tone is totally gone, and for some reason his ears are pink.

"When…it happened, I thought about that."

He gestures toward his abdomen, where she can almost see the outline of the scar through his shirt.

"I mean, I thought about all the things I still had to do, and all the people I'd be letting down if I died. I had a lot of promises to keep."

Once again, she doesn't know what kind of reaction to give him. When the hell did he all of a sudden decide that he was going to be open with her? She's tempted to think that something unnatural has taken hold of him, cracking open before her eyes all the things in his head he'd rather keep secret. But the tense, gruff way he bites off his words, like they taste bitter, is one-hundred-percent Ed.

She swallows. There's not a lot she can say to that. By his own admission, their silly, unkeepable promise to each other had helped him stay alive. And she, with her keen eye and whip tongue, has nothing in her arsenal for this particular admission.

So she whispers, "thank you," and his ears darken even more.

In a few seconds, to lighten the seriousness that has fallen on them, he swings his leg out from under the workbench and taps the plating with one finger.

"Hey, I think I knocked something out of alignment a few days ago. Mind looking at it?"

She sighs. Whether it's automail or bone, he'll never learn how to keep himself in one piece. Still, the most important pieces of him will stay intact. She dragged that vow out of him somehow. So she sighs, and picks up her wrench.

"Ed, for your next big promise, can you please, please, take better care of your automail?"