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A knight could give his prince everything. Katsuki had. Nine years of it, down to the marrow, and he had one thing left to give and it was leaving.
He stood at the eastern wall of the great hall in the armor of the royal guard and watched them bring his prince to the altar. Throughout it all he held still—it was the one skill he had that mattered more than the sword. He had been holding still for nine years. He could do it a few hours more.
Nobody in the hall knew he was already gone. To the two kingdoms assembled, the prince's sworn sword stood his post at the wedding as a sworn sword should.
He had a commission in his belt, sealed and signed, that said otherwise. He'd carried it for eleven days, against his ribs, under the breastplate, where it had gone warm from his own body until it felt like a second heart beating wrong. Effective the morning after the wedding. A posting to the far eastern passes, the worst of the border. This was an assignment men took when they had a death wish or a debt. He'd requested it himself. He'd requested it the same afternoon the herald ended his life in this same hall, and he had told no one. He was going to stand here and watch Izuku be married and then he was going to ride east before he woke. Izuku was going to hate him for the rest of both their lives.
Good, Katsuki thought, and did not believe it, and kept his face still, and watched.
He had loved the prince before he had a word for it, and he had been cruel to him because of it. He had understood the connection between those two facts far too late to undo any of the damage.
The training yard. A soft green-eyed boy who cried when the practice blades drew blood. Katsuki had looked at him, at ten years old, and felt something turn over in his chest that he had no permission to feel, a smith's son, toward a prince. He had done the only thing a furious child knows to do with a feeling he can't afford. He'd made it hurt. He'd called him a waste of good armor in front of everyone, and meant, underneath, look at me. Keep looking at me. Don't ever stop.
Izuku hadn't stopped. That was what ruined Katsuki's entire life. You could hit him and hit him and he came back green-eyed and stubborn and still looking, and every year the looking got harder to survive. Every year Katsuki got better at being a sworn sword because the sword was the one place he was allowed to be as much as he actually was.
He earned the knighthood the hard way. He was common-born, with no name behind him but the one he beat into people. He took the border campaigns nobody wanted. He took a blade through the forearm for a captain he despised, because a knight did that. Taking a blade was something he was permitted—a way to spend the enormous surplus of himself that had nowhere legal to go.
And then the crown, in its wisdom, had sworn him to the protection of the prince he'd spent his whole boyhood failing to stop watching. Katsuki had knelt and taken the oath with his still face on and gone home to the guard's chamber and put his fist through a wall.
He understood, kneeling, exactly what he'd been handed. A life at Izuku's side. A life that was as close as he would ever be allowed and not one inch closer. The oath was a door with a lock and the crown had just handed him the key and told him he was forbidden to use it. Forever. For honor.
He had thought, that first year, that it would kill him. It hadn't. That was almost worse. You could live inside an impossible thing for a very long time. You could build a whole life in a room the size of a swallowed word and call it enough, because the alternative was calling it what it was.
The border keep. December. The worst three days of Katsuki's life, and he had been to war.
Izuku went down in the snow with a spear in his side and Katsuki's whole body had understood, in the half-second before his mind caught up, that if he died then Katsuki was going to walk into the eastern sea and keep walking. He had gotten Izuku to the keep. He had held the wound closed with his own hands in the back of a wagon for six hours. He had not slept for three days, sitting in a chair by a cot, because sleeping meant not watching—not watching meant he might stop breathing while Katsuki's eyes were shut. Katsuki was not, was not, going to let go of the blanket at Izuku's hip, not for anything, not for anyone.
When Izuku woke, he'd said Katsuki's name. The softer version, the one from before the were men. Kacchan. He'd reached up with his fever-clumsy hand, reaching for Katsuki's face, and every cell in Katsuki's body had leaned toward it like a plant toward the one window in a cellar.
Katsuki had caught the hand halfway and pressed it back down.
That was what Izuku would never understand about the border keep. It lived in Katsuki like a stone: that catching that hand and pressing it back down had been the hardest single act of his life. Harder than the knighthood. Harder than the blade through the arm. He had wanted to turn his face into that palm and say the word and be damned for it, be stripped of his spurs, be exiled, be anything, if it meant one honest second. But he hadn't. Because Izuku was fevered and half-dreaming. If Katsuki took that hand it would be theft and Katsuki would not, would not, be a man who took what wasn't freely his.
Izuku would never be freely his.
So he pressed his hand down. He shut his eyes. He said nothing. He held the line.
He would hold the line for six more years, and then, one night, Izuku clear-eyed and grieving and asking, please, just once, come here, he would finally get to stop holding it. It would turn out that stopping was the beginning of the end and not the end of anything at all.
Here is what Katsuki had, in nine years, guarded like a man guards a wound so no one sees how deep it goes:
The right to stand at Izuku's back in every fight. The right to taste his food. The right to be the last face he saw before a council and the first after. A honey-slicked thumb and three seconds of a look he'd carried for two years like contraband. The right to sleep in a chair on the bad nights, close enough to hear him breathe, near enough to lie to himself that nearness was a kind of having.
He had the religion of devotion and none of the love itself, and he had built a life in it. It had been, God help him, enough. It had been enough right up until the letter came from the west with peace inside it, and Katsuki knew that his lifetime of almost had just been given a last day on the calendar.
He found out the way the whole court found out. A herald. In this hall. In front of everyone.
He had been proud of his face, later, in a bitter way. Nine years of holding still had built him a face that could take the news of the royal betrothal and show nothing. The knuckles on his pommel went white—he'd felt his grip tighten and couldn't for the life of him stop it—and one muscle in his jaw had betrayed him. But his face held, and to two hundred people the prince's sword received the death of everything he was with the correct still dignity of a loyal man.
Only Izuku had seen. Their eyes had met across the crowded hall for the length of one heartbeat, and Katsuki had let Izuku see, on purpose, the only gift he had left to give in that moment: the truth, for one second, before he bowed and buried it. When he bowed it was deep and perfect. Then he had gone back to the wall.
That same afternoon, while the court buzzed with the news of the peace, Katsuki had walked to the marshal's office and requested the eastern passes.
He'd known, requesting it, exactly what he was doing. He was not built to stand at the wall of Izuku's marriage for the rest of his natural life. He knew his own limits the way he knew his own reach with a blade. He had a great deal of limits and they had a floor, and the floor was this: he could hold the line they could not across a closed door for nine years, but he could not—would not—be able to hold it across a marriage bed. Not with Izuku ten feet away every night belonging by law to someone else. He would break. He would reach for him in some dark hour and Izuku, grieving, would let him. It would become the thing the ballads warned about, the affair that rots a crown from the inside. The peace Izuku had bought with his own gutted heart, the peace that would keep the border boys from dying in the snow the way Izuku almost had, would curdle. Because of Katsuki. Because Katsuki couldn't hold the line they'd drawn.
So he would remove the line's temptation. He would take himself to the far end of the kingdom and let the marriage be untainted by him. It was the last thing his fealty could do for the prince he'd sworn to protect: protect him from Katsuki. Protect the peace from the one man in the realm who'd burn it down for a single honest hour.
It was the most loyal thing he had ever done. It was going to look, from where Izuku stood, exactly like a knight breaking faith and abandoning his prince on the worst morning of his life. Katsuki was going to let it look like that. Because the truth, I'm leaving so I won't ruin you, was a truth that would only make Izuku try to stop him. Izuku could not be allowed to stop him, because Izuku, given the chance, would choose Katsuki over his own honor. Then there would be no one left to keep Izuku honorable except Katsuki, who was leaving precisely so he wouldn't have to watch himself fail at it.
Let Izuku hate him. Hate was survivable. Katsuki had taught him hate first, in the training yard, a whole lifetime ago. If hate was the last thing he could give Izuku that would keep him safe, then Katsuki would give him that too, the way he'd given him everything, all of it, everything but the word love.
The sovereign of the west found him once, before the wedding. Katsuki had not expected that.
They came to the training yard where he was working the pells alone, past dark. It was what he did on the nights he couldn't sleep. They stood at the rail and watched him for a while, this young grave kind stranger who was going to marry Izuku, and then they said, quietly, with no cruelty in it at all:
"You're the knight. Izuku's sword. The one who carried him out of the collapse in the south." A pause. "The one he can't stop not-looking at."
Katsuki had said nothing. He'd kept working the pell.
"I'm not a fool," the sovereign said. "I saw it the first day. The way a room arranges itself around the two of you. I'm to marry a man whose heart is out here holding a sword, and there's nothing to be done about it. He's good, and he'll try, and I'm good, and I'll try, and we'll build something real out of trying because that's what people like us do with the hands we're dealt." They'd looked at Katsuki with those honest eyes. "But he'll never be wholly mine while you're at his side. And I find I don't want him to be, not like that, not a man cut in half for the rest of his life. So I'll not stop you leaving, if you're leaving. I can see that you are." A breath. "I won't tell him it was mercy. If he knew you left to save us both, he'd never forgive himself, and he has enough to carry. Better he thinks you a coward. Kinder. Let me give him that much."
Katsuki had stopped working the pell.
"You're a better person than me," he'd said, finally, to the stranger who was taking the only thing he'd ever wanted.
"No," the sovereign said, gently. "I just have less to lose." And they'd gone back inside, to the warmth, to Izuku, and left Katsuki alone in the dark with the pell and the commission warm against his ribs and the understanding that Izuku was marrying someone who deserved him. It was the one thing Katsuki had prayed against without ever admitting he was praying.
He had gone through the connecting door that last night knowing it was the last night.
He'd hold this secret to his own chest and carry it east: that when Izuku said just once, please, come here, and Katsuki crossed the room, Izuku thought he was stealing an hour out of a lifetime of nearness. He thought that after the wedding there would still be the wall, the corridor, the disciplines, the terrible ongoing almost. Izuku thought the grief had a floor, and the floor was at least he'll still be near me.
And Katsuki had known, crossing that room, that there was no floor. That he'd be gone within days. That this was not a stolen hour inside a long life; it was the last hour, the only one, and after it there would be no wall to look for him at, no corridor, no chair by the bed, nothing. He'd let Izuku believe otherwise. He'd let him have the smaller grief and kept the larger one for himself, because Izuku was going to walk to an altar in a few hours and Katsuki was not going to send him there having just learned he was being abandoned too. One catastrophe at a time. It was the only mercy Katsuki had the heart for.
There's something I have to tell you, he'd said, into Izuku's hair, when they were wrecked and tangled and it was almost dawn. Not tonight. I can't. But there's a thing, and when I tell you, you're going to— and he'd stopped, because how do you finish that? You're going to think I'm the worst kind of coward. You're going to think of me as the knight that ran. And you're never going to know I ran toward the passes so I wouldn't run toward you.
Remember I couldn't tonight, he'd said instead. Whatever you think of me after. Remember I had one night and I didn't want to spend it on the thing that ends it.
And Izuku, who thought he'd already lost everything and so couldn't imagine there was more, had said then don't tell me. Katsuki had held him until the window went gray, memorizing him, the weight and the smell and the exact sound of him breathing, laying it all down in the one part of himself that no oath and no border and no marriage could confiscate. It was the part he'd take east and live on for the rest of his life like a man rationing bread through a winter that would not end.
He had wanted to say it so badly, that last night, that his teeth ached with holding it. It had risen up in him, in the dark, when there was nothing left to lose. He'd felt Izuku feel it, felt him go still against him waiting for it, but Katsuki had bitten it back one final time.
Because if he said it, Izuku would say it back. He knew that now, if he'd ever doubted it, which he hadn't, not really. He'd known that love was a word the both possessed for each other since the training yard. Izuku would say it back and it would exist between them, a real thing spoken and then immediately lost forever at an altar at dawn. Katsuki could survive a great deal. He could survive nine years of a locked door and a swallowed word and a life measured out in the space between two people who never touched. He could survive the passes, and the winters, and the hate.
He could not survive hearing Izuku say it and then watching him marry someone else three hours later. That was the thing. That was the floor.
So he kept the word. He rode east with it still in his mouth. It was the last thing of Izuku's he had any right to—the only thing he'd never given away.
That was still to come. First there was the wedding, and Katsuki stood his post and watched it, because he'd be damned if the last thing he ever did for Izuku was flinch.
They brought him in in white and silver. Katsuki had seen him in armor and in blood and in fever and, once, wrecked and open in the dark with his hands in Katsuki's hair, and he had thought there was no version of Izuku left that could hurt him worse than the ones he'd already survived. He was wrong. The white and silver was worse. Izuku walked to his own selling with a straight face, the face Katsuki himself had taught him without meaning to and Katsuki stood at the wall. He recognized his own armor worn on the one person he'd have died to keep from ever needing it.
The sovereign of the west waited at the altar, brave-faced. Katsuki did not hate them. He'd have given a great deal to be able to hate them. It would have been easier than the alternative, which was standing at the wall watching two good people be gentle with each other's grief while his own heart got made into a treaty in front of two kingdoms.
The priest spoke. The hands were joined. The cord was laid across the wrists.
Katsuki held still.
He held still through the blessing and the binding. He held still while the priest gave Izuku the old words to repeat, the vow, that ended the war and joined the houses and took the him of Katsuki's reach forever and legally and with the blessing of two faiths. He held still, and he had almost, almost made it. He only had to hold for the length of one vow.
And then, in the half-second before Izuku spoke, the man's eyes came off the sovereign and found the wall.
Found Katsuki.
Their eyes met. It lasted a second, maybe less. It was the training yard and the border keep and the crowded hall and the last dark hour all at once, nine years folded down into a single look across a wedding. Katsuki understood what Izuku was doing, understood it with a clarity that nearly took him off his feet: he was giving him the vow. Was looking at Katsuki while he said the words, so that some buried unspeakable part of the giving himself over would be aimed at the wall. So that Katsuki would have that, at least. The words, pointed at him, even as they left Izuku's mouth for someone else.
It was the cruelest kindness anyone had ever done him and Katsuki took it greedily, the way he'd taken every scrap of nine years. It was the last kindness and there would never be another.
"I, Izuku, of the house of the east," Izuku said, looking at his knight, his voice not shaking because Katsuki had taught him how, "take you—"
And Katsuki held still, held eye contact, and let him finish it. He let him say all of it, every word, aimed at the wall and landing in a stranger while Katsuki stood in his armor and received the words he would never be given honestly. He did not move, did not fall, and did not once look away. Izuku would have somewhere steady to look while he gave his life away for the border boys and the grain and the peace.
It was the last thing Katsuki did as the prince's sworn sword. He was a steady place to look. He'd been trying to be that for nine years. He got to be it, one final time, all the way to the end of the vow, and then the priest bound the houses and the hall erupted and it was done. The man he was in love with was married. Katsuki bowed his head at the wall like every other guard in the hall and let his still face keep the last of his secrets.
He rode out before dawn.
He didn't say goodbye. They had never said the true things out loud and he was not going to start with that one, and anyway there was no version of a goodbye that survived contact with Izuku's face, so Katsuki didn't risk it. He saddled the horse himself in the dark. He left the guard's chamber exactly as it had always been, the chamber that connected by a single door to a room that wasn't Izuku's anymore. Now it belonged to a marriage. He did not open the door, not even to look, because looking was a thing he could no longer do without jeopardizing the rest of his life.
He left a letter. He gave it to the one page he trusted, with instructions to deliver it after the sun was up. After Katsuki was well beyond the walls, beyond recall, too far east for anyone to ride him down and demand he explain himself or, worse, ask him to stay.
He'd written it three times and burned the first two. The third was short. He was not a man of many words and he had spent his whole life proving it. He was not going to be a poet now, at the end, when it couldn't do anything but hurt.
He didn't put the reasons for leaving in it. Not the passes-instead-of-the-prince, not the sovereign's mercy, not the floor he couldn't survive. Let Izuku think him a coward. He put none of the truth that would make Izuku try to forgive him.
He put only one thing. The thing he'd swallowed in a border keep and swallowed in a stolen bed and swallowed for nine years across a locked and lawful door. He wrote it in his blunt swordsman's hand.
He wrote one word.
Just the word, and Izuku's name, and his own beneath it. The whole of everything he had in the one direction it could never be answered, from a saddle, in the dark, riding away as fast as he could go.
Katsuki had learned the same thing his prince had learned, though neither of them would ever get to tell the other so: that a man like him could only say the truth out loud when it was safe. And the word love was only safe when it was useless. When it couldn't be answered. When there was a wedding, or a border, or the whole width of a kingdom between saying it and the ear it was meant for.
Izuku had said his love aloud to a stranger, looking at Katsuki.
Katsuki said his to Izuku, riding away from him.
The sun came up over the eastern passes.
Somewhere behind him, in a room that used to have a door to his, a page was climbing the stairs with a letter. A married prince was about to read a single word in a blunt familiar hand, and reach for a wall that was no longer standing there. He'd find, where his knight had been for nine years, only the cold clean morning, and peace, and the whole rest of his life.
Katsuki did not look back. He had never once, in nine years, been able to turn around at the right time. He wasn't going to learn how now. He rode east into the sun with his love finally said and no one left to say it to. That, in the end, was the truest fealty he had: to love Izuku exactly as much as he always had and to prove it by being gone.