Chapter 1: The Dark of the Moon
There are three rules for the new moon, and you wrote all of them yourself.
One: from sunset to sunrise, the seal on the shrine loosens, and the King of Curses may walk the grounds inside the outer torii. Not one step past it.
Two: the keeper must be present, within the grounds, from the first star to the first light, or the seal fails entirely and does not come back.
Three: while the keeper is inside the grounds, Ryomen Sukuna may not cause her harm. Not with his hands, not with his technique, not with any curse he could call. You had that one carved into the vow in three different phrasings, because you are your grandmother's granddaughter and she taught you that a binding vow is a contract with something that has had a thousand years to find the loopholes.
You were twenty-five when you made it. You were the only barrier specialist left standing in the rubble of Shinjuku with enough cursed energy to try, and the price of sealing something that far above your grade was this: twelve nights a year, dusk to dawn, alone on a mountain with him.
It's the seventh new moon. You're twenty-six now. The stone steps up to the shrine are wet with July rain, and you are carrying a cooler full of groceries, because three months ago the King of Curses informed you that if he was to be caged like a dog he would at least eat like a king, and you, God help you, said fine.
He's waiting on the veranda of the main hall when the last light goes out of the sky.
He doesn't appear. He's simply there, the way a shadow is there when you finally notice it: sitting on the edge of the boards with one knee drawn up, the white sleeves of his kimono pushed back, four arms arranged with insulting ease. Two rest on his knee. One props his chin. The fourth, lazily, is turning one of your grandmother's prayer beads between finger and thumb, which he has no business touching.
He wears the body he made for himself from the last of his fingers, after the war ended and before you caught him: tall, heavily built, the black markings of his curse sweeping under his eyes and across his cheeks. Four eyes, the lower pair set beneath the upper, all of them a red so deep it's nearly black in the dusk. A seam runs across his abdomen where the second mouth lies closed. His hair is the colour of cherry blossom in a fire.
"You're late," Sukuna says.
"The sun is literally just setting."
"You were late in spirit." The upper eyes take you in, top to bottom, unhurried. The lower ones go to the cooler. "What did you bring me?"
"Mackerel. Shiso. Rice. A daikon, for some reason, because you told me to bring a daikon, and you've never once told me why."
"Because you don't know how to choose one," he says, and stands.
He's enormous on his feet. He always forgets to make himself smaller and you always forget to be ready for it. He comes down the steps, and the cursed energy rolls off him like heat from an oven door, prickling the hair on your arms. You don't step back. You stopped stepping back in the second month, when you understood that rule three held and that what he wanted most was to watch you flinch.
He takes the cooler from you with one hand. With another, he lifts the daikon out and holds it up to the light from the stone lanterns.
"Soft at the shoulder," he says. "Woody. Thin-skinned in the wrong places. This radish has suffered. Did you choose it with your eyes closed?"
"I chose it at a convenience store at four o'clock because the farmers' market was closed."
"Then you deserve what you get." He tosses it back to you and walks into the shrine kitchen, and you follow, because there are rules and because, God help you twice, you're hungry.
The first month, he spent the whole night trying to break you.
Not your body; rule three held, and you watched him find that out, watched him reach for you with all four hands and stop a hair's breadth from your throat as if he'd hit glass. So he went for your mind instead. He told you what he'd done in Shinjuku in exact detail. He told you the names of every sorcerer who died there and how each of them had sounded. He told you, in a low and interested voice, what you would taste like. You sat on the veranda with your back to a pillar and your hands clenched in your lap and you did not cry until you were in the car at dawn.
The second month, you brought a book. You read it aloud, badly, all night, mispronouncing the hard kanji on purpose. Around three in the morning he snatched it out of your hands and finished the chapter himself in a voice like smoke, and then he told you the author was a fool and spent an hour explaining why. You argued. You were right about half of it. He conceded none of it.
The third month, he asked what you'd eaten that day. You said a convenience-store onigiri in the car. He looked at you with such profound disgust that it was almost funny, and then he made his demand about food, and the war between you turned into a different kind of war.
Now it's the seventh month, and you are sitting on an upturned crate in the shrine's ancient kitchen with your chin in your hand, watching the King of Curses fillet a mackerel.
He doesn't use a knife. He doesn't need to. He holds the fish in two hands, bends his head over it, and the air moves: a whisper of Dismantle, so fine and so controlled it doesn't even scratch the cutting board beneath. The fish opens like a book. The bones lift away in one piece. The skin comes off in a single silver sheet.
You've seen that technique take a building down to the foundations. You've seen what it does to people. Watching him use it like this, with total precision, to prepare your dinner, does something unwelcome to the back of your neck.
"Stop staring," he says without looking up.
"I'm not staring. I'm supervising."
"You're thinking about it cutting you instead." The lower pair of eyes slides toward you. "You're thinking about how close it would come. Whether you'd feel it."
"I'm thinking you'd make a terrible sushi chef. No customer service."
"I had a cook once," Sukuna says, sliding the fillets into a pan where they hiss. "Uraume. Loyal to the last, which was very inconvenient for everyone who met them. They could do things with ice and a blade that would make you weep." The fourth hand flicks salt over the pan from a height. "I taught them everything they knew."
"You taught them to cook people."
"I taught them to cook." He turns the fish. The skin crackles. "What they cooked was their own concern."
He serves you at the low table on the veranda, because he says eating indoors on a summer night is a peasant's habit. The mackerel is perfect. The rice is perfect. He grated the miserable daikon with something that wasn't quite a hand and wasn't quite his technique, and it melts into the soy and tastes like the best thing you've eaten all year.
He doesn't eat. He watches you eat, sprawled on his side across the boards with his head propped on one fist and his other three hands doing nothing at all, which on him is the same as doing something.
"Well?" he says.
"It's good."
"It's perfect."
"It's very good," you allow, and he laughs, low and rough, and the lanterns flicker.
You put your chopsticks down. The night is hot and heavy, cicadas going in the cedars, and the moon is somewhere on the other side of the world, and you have five hours left. You've never let yourself think about that number before. You find yourself thinking about it now.
"Why do you do this?" you ask.
"Do what?"
"Cook for me. Read to me. You could spend the whole night sulking in the main hall. You did, in month four."
"I was considering ways to kill you that rule three wouldn't cover."
"Find any?"
"Several." He smiles, slow and sharp. "None I liked."
He reaches out. Not for your throat. One of his lower hands, the left, comes across the table and his thumb touches the corner of your mouth, where there's a grain of rice you hadn't noticed. He takes it. He keeps his hand there. He's touching you, and you feel the faint shimmer of the vow between his skin and yours, alert, waiting to see if this is harm.
It isn't. The vow lets him through.
The red eyes narrow, interested. He felt that too.
"Huh," Sukuna says softly.
Your heart is going hard enough to see through your shirt. He can definitely see it. All four eyes are on you now and his thumb moves, a slow drag along your lower lip, and you could pull away. Rule three means you could pull away and he could do nothing about it, and both of you know it, and you don't.
"Listen carefully, keeper," he says. "Because I will only say this once, and I don't say anything I don't mean." His voice drops. "I have taken whatever I wanted for a thousand years. Cities. Clans. Bodies. Teeth. I never asked for a thing in my life." His thumb presses, just slightly, until your lips part. "I won't take you. Not because of your little rule. I could find my way around it in a month. I won't take you because I want something better."
"What," you manage, "could be better than taking?"
"You," he says, "asking."
He lets go. He leans back on the boards as if nothing happened and picks up your grandmother's prayer bead again, rolling it between two fingers, and the whole night tilts sideways and doesn't come back.
You don't ask. You sit there with your mouth burning where his thumb was and you don't say a single word until the sky over the cedars starts to grey. He doesn't push. He tells you a story about a fox spirit he once ate in Nara. He critiques your posture. He reminds you that the daikon was a disgrace.
At the first bird, you stand. You lay your palms on the shrine's central pillar and pour your cursed energy into the seal, and it knots tight again around him like a fist closing. He goes still. In a moment he'll be gone back into the dark, sealed under the floor of the main hall for another month.
At the top of the steps you turn back. You don't know why. You'd swear afterwards it was the vow making you do it.
"If I asked," you say. "What would you do with it? A whole night?"
Sukuna is already half shadow. His teeth gleam in it.
"Every minute," he says. "Come back next month and find out."