Chapter Text
The cold seeped into Yuuji’s very bones. Water lapped at his sides, his clothes soaked and clinging to his body. With his eyes still shut, he took a deep breath, only to cough and splutter as the water shot up his nose.
Yuuji pushed himself upright, spluttering, grimacing at his soggy clothes, rubbing the excess water off with numb, shaking fingers. He looked around warily. The last thing he remembered was banging on the prison bars of his own mind as Sukuna batted his friends around like a cat with a bug. Now, he was laying in a shallow pool whose edges seemed to vanish into middle distance. The frigid water looked red, almost like blood, and the scent of mold and iron filled his nose.
He glanced around, searching for any sort of landmark or break in the monotony. There was nothing near him, not counting the water that covered the ground. Thick bars of bone stretched overhead like an ossified trellis before plunging into the murky ground. The curved shape of the bones kind of reminded Yuuji of a ribcage.
Far off in the distance was something white, a lumpy pyramid that rose out of the water. Yuuji squinted, trying to make out the details, and in the blink of an eye he was at its base, his stomach lurching. Water sloshed around his ankles as he came face-to-face with a twisted wreath of bovine skulls. A mountain of bone. Its shape dragged Yuuji’s eyes up to the top, where it culminated with a slim figure, robed in white, lounging against the jagged edges of shattered bone like he couldn’t feel them digging into his skin.
“...Sukuna?” Yuuji asked. He hadn’t seen the specter who lived inside him before. From Gojo’s descriptions, he had expected some huge and raging beast, many-eyed and many-faced, large enough to use his femur as a toothpick. He hadn’t been expecting something humanoid.
He certainly hadn’t been expecting something wearing his own face.
Ignoring the extra set of eyes that Yuuji could see slitting themselves open on Sukuna’s cheekbones, and the menacing aura of bloodlust and doom, Sukuna looked like he could have been Yuuji wrapped up into a set of formal robes.
Sukuna was…striking. Against the near-monochrome backdrop of the domain, all deep, dark reds and murky blacks, his bright pink hair and pristine white kimono were a disorienting pop of color. His face was covered in bold lines and pointed curves that perfectly mimicked the sharp angle of his jaw, highlighting the eerie symmetry of his features. His eyes were red, redder than anything Yuuji had ever seen before, and framed by long lashes, they seemed to glow in the dim light.
With perfectly-shaped lips, Sukuna sneered. “Who else? You really are as dumb as you look.”
“Hey!” Yuuji said. “You’re wearing my face too, you know!”
“Don’t remind me,” Sukuna spat. “And don’t look up at me without my permission.”
Yuuji narrowed his eyes. “Come down here, then,” he said, letting a slow grin spread across his face. “I’ll look down on you instead.”
Sukuna laughed. “Oh, funny,” he said, standing up from his spot nestled amongst the bones.
Before Yuuji could react, Sukuna darted forward, appearing in front of him in a blur of claws and teeth. Sukuna landed on him with both feet pressed into his chest, pushing Yuuji back, sending him skidding across the shallow surface of the water like a skipping stone. When he finally rolled to a halt, Sukuna was already crouched on top of him, wooden sandals digging uncomfortably into his chest, clawed fingers reaching forward.
“Wh—hey!” Yuuji shouted, thrashing as he tried to push Sukuna off.
Sukuna reached down and grabbed his bicep, wrenching it outwards until his shoulder dislocated with a sickening pop.
Yuuji gasped, his mouth open in a silent scream, and Sukuna grabbed his chin with his other hand, forcing his mouth to stay open as claws dug into his cheek. “Stay still,” he hissed.
“Fuck you,” Yuuji spat, grabbing Sukuna’s wrist with his other hand. “I’m gonna rip you to shreds!”
“You’re so angry,” Sukuna mused. “Where was all this rage earlier?”
“You killed me, you bastard!” Yuuji howled.
Sukuna tutted, squeezing his jaw hard enough that Yuuji heard the bones creak. “Are you forgetting how I healed your arm and took care of that curse for you?”
“Yeah, and then you ripped my heart out,” Yuuji hissed. “You sadistic motherf—”
“Shut up,” Sukuna said coldly, and stood up, keeping his grip on Yuuji’s jaw tight. He raised his arm up so he was holding Yuuji with one hand, his feet barely dangling over the surface of the lake. “I want to know how you did that.”
“How I did what?” Yuuji said, kicking his feet. He only managed to get his toes to brush the fabric of Sukuna’s kimono before Sukuna’s hurling him back across the water, flying ass over teakettle until his body slammed against the base of the mountain of bone.
“How you used that technique,” Sukuna hissed. “Tell me. I don’t like repeating myself, boy.”
“I told you,” Yuuji said, pulling himself into a half-upright position and rubbing his head. “I’ve been able to do that since I was a little kid.”
“Bullshit,” Sukuna snapped. “How does a pathetic worm like you have my cursed technique?”
“Yours?” Yuuji asked, his mouth dropping open. “What—no! No way, no way, no way! There’s no way it’s yours!”
Sukuna glared at him. “Funny,” he said, “I feel the same way. It’s quite convenient,” he continued, stalking towards him, his kimono billowing over the red water, the white cloth remaining pristine, untouched. “That some nobody shows up to swallow my finger, successfully cages me—something that should be impossible—and then casually wields my cursed technique. Tell me, how likely is it that some no-name brat without a lick of magical talent, who shows up out of nowhere, happens to be not only my vessel but my… soulmate?” He spat out the word like it left a bad taste in his mouth. For all Yuuji knew, it did; maybe evil incarnate can’t even talk about positive things like love and happiness without feeling sick.
“I don’t know,” Yuuji protested. “It’s not—I mean, I could see curses, but I didn’t even know what they were until a few weeks ago. I just thought they were, like, monsters that only I could see.”
“Who sent you?” Sukuna asked, crouching in front of Yuuji, his cold gaze trained on his face. “Who trained you? What do your masters want?”
“Wh—nobody sent me! I don’t have any masters!” Yuuji said, pushing himself out of the water with one palm, even as his dislocated arm throbbed with the motion. “And I trained myself!” He shook his good fist out, letting the blue flames lick up his arm. “See?”
Sukuna watched the cursed energy flicker around his fist, his eyebrows furrowing together. “Well, with how poorly you control your cursed energy, I suppose that’s not hard to believe,” he said. “Although, you could always be feigning incompetence to gain my trust.”
“Ugh!” Yuuji exclaimed, letting the flames dissipate and throwing his hand in the air. “Like I would want your trust!” He pointed a finger at Sukuna accusingly. “And I don’t need to feign incompetence, either!”
Sukuna snorted. “Clearly not.”
“Wh—hey!” Yuuji spluttered. “That’s not—I didn’t mean it like that, bastard!”
“The irony,” Sukuna said, settling back on his heels, “that after a thousand years of slumber, I awaken only to be trapped inside the soul of some pathetic brat who can barely wield cursed energy. And then that vessel has the audacity to think he’s my soulmate?”
Yuuji glared at him. “Why would I think that? I don’t even know what your cursed technique is!”
Sukuna blinked. “You…don’t?”
“No!”
“They didn’t tell you that after you became my vessel?”
“No!”
“Hm.” Sukuna pursed his lips. “Well. Perhaps a demonstration is in order, then.” He stood up, grinning down Yuuji.
Yuuji had a brief moment to think oh, crap, and then there was a bright flash of pain, black spots popping in front of his vision. When he opened his eyes, his arms were resting on either side of him, blood pouring out of the stumps. He gaped at the exposed cuts of muscle, then turned his eyes to Sukuna, wide-open in disbelief.
“My cursed technique,” Sukuna explained. “Well, one of them. Dismantle is typically lethal, but…” he grinned. “I adjusted its strength, just for you. It wouldn’t do to have you die too soon.”
“I’m already dead, bastard,” Yuuji hissed.
“Are you?” Sukuna asked, sounding bemused. He reached out towards Yuuji, who flinched away, but Sukuna merely placed his thumb on the center of Yuuji’s forehead, mirroring the placement of his own tattoos.
Yuuji groaned as the flesh of his shoulders twitched, then pulsed, then surged forward in a burst of too-hot too-dull muscle and bone. He willed himself not to look as his arms regrew—it was nauseating enough already, heavy and gut-wrenching and wrong, his stomach twisting with the sickening feeling of flesh twisting and warping against the constraints of nature. He could feel his cells splitting in real-time, too many to count, spewing forth ligament and tendon and bone and skin.
Sukuna’s thumb pulled away from his forehead, and Yuuji slumped forward, panting. “You can open your eyes.”
Yuuji groaned, cracking his eyes open just a slit, enough to see Sukuna’s feet and the fluttering hem of his white kimono. He brought his arms up to inspect them. Moving them hurt—the insides felt scraped raw, the skin overly sensitive. Hesitantly, he curled one hand into a fist, hissing at the prickling sensation of muscle against skin.
“The pain will fade,” Sukuna said dismissively. “Come on, stand up. For daring to lie to me, I’ll beat you into the ground, again and again, until you’re begging for mercy that will never come.”
Yuuji gritted his teeth and pushed himself up, ignoring the pain that flared up his arms. “I think you’ve got it backwards, old man,” he ground out. “You’ll be the one begging me—”
Sukuna kicked him in the chest. Yuuji went flying backwards, scattering skulls and broken shards of bone in his wake. He lurched upright, rolling over just as Sukuna crashed into the spot where he’d landed. The sharp horns of the cow skulls gouged into his skin, but Yuuji ignored the cuts, summoning his blue flames and aiming a punch at Sukuna instead.
The King of Curses definitely outmatched him. No wonder Fushiguro and Kugisaki had looked so roughed-up when Yuuji regained control of his body. Sukuna moved like a force of nature: every move Yuuji threw at him, he had already anticipated; every punch was blocked or dodged.
And he wasn’t even using his cursed technique. Yuuji knew Sukuna could chop him into tiny pieces and scatter them across the floor of this weird realm of bone and blood with just the flick of his fingers if he so wanted. This fight—if you could even call it that—was just the curse playing with him, like a cat batting a mouse across the floor.
Was this what the rest of his (after)life would be like? Was Yuuji in hell, doomed to an eternity of getting his limbs sliced off and regrown, while Sukuna toyed with him, testing the depth of the agonies he could drag him through?
“Pathetic,” Sukuna jeered, batting Yuuji’s punch aside. “Worthless, hopeless. You’re so weak, what makes you capable of containing me?”
“I’m not weak!” Yuuji shouted.
“I’m at a fraction of my power and you could still never hope to beat me. Do you like lying to yourself that much?”
“Fuck you!” Yuuji spat, and then thought fuck it, Sukuna’s going to torture me either way. He raised his hand up, letting his fingers curl as if his nails were sharp claws, and slashed downwards. “Slash!”
The technique roared towards Sukuna with a surge of cursed energy. Yuuji could almost see the thin blue lines as they sliced through the surface of the water. Sukuna paused, standing in place, staring at the oncoming wave of cursed energy. He wasn’t even bothering to dodge. Overconfident piece of shit.
Yuuji’s Slash hit Sukuna dead-on, gouging deep lacerations into his chest and arms. The fabric of his kimono split open, revealing a deep cut on the surface of his chest that immediately began to pour blood, a mockery of the lethal wound he had inflicted on Yuuji’s body earlier.
The kimono turned tacky red. Sukuna took a step backwards, still staring down at his chest. The cut didn’t go all the way through him—of course not, why would Yuuji ever be so lucky—but it’s definitely there. He hit Sukuna!
“Wh—” For the first time, Sukuna seemed to be at a loss for words. He whipped his head up to stare at Yuuji, his jaw working soundlessly. The red water that covered the domain began to churn, splashing over Yuuji’s tatty sneakers.
Finally, Sukuna spoke. “You know…I thought you were faking it, the first time. It should be impossible for you to use that technique. And yet….” He trailed off, staring at Yuuji like he’d just uncovered something fascinating yet nauseating.
“What, seriously?” Yuuji spluttered. “That’s really your technique? Are you sure?”
“Of course I’m sure,” Sukuna scoffed. “You think I can’t recognize my own cursed energy? This is my curse you’re using.”
Yuuji deflated, his desire to fight draining out of him. “So you’re telling me….”
“It would appear that you have my soulmate gift, brat,” Sukuna said, sighing. “Unbelievable. Lifetimes spent without it, and now I’m saddled with—” He grimaced and gestured vaguely at Yuuji. “—that.”
“Wh—you just gestured at all of me!”
“Exactly,” Sukuna said, rolling his eyes. “This must be a fluke.”
“A fluke?” Yuuji said, narrowing his eyes. “Soulmates aren’t flukes.”
“Curses don’t have soulmates,” Sukuna replied. “And our power levels are hugely disparate.”
“The power levels for soulmate gifts aren’t correlated,” Yuuji argued. “Besides, I have two gifts anyway. And—and hey, what’s your soulmate gift, huh? What did you get from me?”
Sukuna turned to look at him, regarding him with caution and renewed interest. “Two gifts?” he asked, sounding curious.
“Two gifts,” Yuuji confirmed, crossing his arms. “I’ll tell you the second one if you tell me what your soulmate gift is.”
“It’s likely that your other gift is the ability to manipulate cursed energy,” Sukuna said. “Since you’ve been able to do it ‘all your life.’”
Yuuji got the feeling that if Sukuna knew what air quotes were, he would be doing them. “Okay, fine, it is,” he said, sighing. “But you must have gotten something.”
“Even if I had, brat,” Sukuna said, “it wouldn’t be any of your business.”
Yuuji wanted to hit something. Preferably Sukuna. “How is it not my business? You’re living inside my body. I have your cursed technique because you are my soulmate. It literally could not be any more my business if I wanted it to be.”
Sukuna rolled his head on his neck, cracking it lazily. “If you can land another hit on me, I’ll consider it,” he said primly.
Yuuji grit his teeth and scowled. “What do you mean, ‘if?’”
“I mean,” Sukuna said, “you’re so pathetically weak that it makes me—”
He’s forced to jump back as Yuuji launches himself forward, punching the ground where he had been standing with a deafeningly loud crack. He landed atop the mountain of bones, kimono fluttering with the movement. “—laugh,” he finished, chortling. “Is that all you’ve got? Impress me, Yuuji Itadori. Show me that you’re worthy of being the King of Curse’s soulmate.” His words dripped with malice, mocking and cruel.
Yuuji’s face screwed up in concentration as he attacked, sending a relentless barrage of punches and kicks and the occasional hurled skull towards Sukuna. Every so often, he managed to send a Dismantle towards him, but the flow of his cursed energy was so stilted and awkward that Sukuna easily avoided every attack.
It was sad, really. The brat wanted so badly to belong to Sukuna, yet he couldn’t even make use of the one thing that tied them together.
“It’s not—about—worthiness!” Yuuji gasped in between attacks. “Soulmates are about—connection—the person that understands you best—”
Sukuna stepped in close, closer than he had to, just to sucker punch Yuuji square in the diaphragm, hard enough to send him stumbling back. “You don’t understand me,” he sneered. “You never will.”
Yuuji landed firmly on his ass, barely managing to catch himself before his torso splashed back into the water. “What if I want to?” he asked.
“You don’t,” Sukuna said. “I’m the King of Curses, you moron. I’ve killed thousands and bathed in their blood. And you, what? Spend your spare time nursing sick kittens back to health? We have nothing in common.”
“How do you know if you won’t even give us a chance?”
“There is no ‘us!’” Sukuna spat, and with a flick of his fingers sent a rolling tsunami of cursed energy towards him. It hit Yuuji with a sound like a squelch and a howling wind, tearing through the hasty block he had thrown up. The splashes as Yuuji hit the ground were almost musical, a symphony of gore that brought a genuine smile to Sukuna’s face.
He strode over to the spot where Yuuji had landed, face-down, and helpfully rolled him over with his foot. Yuuji gasped as his face was brought out of the water, choking on blood-flecked air.
Sukuna sent a critical eye to the body parts floating in the water. Chunks of leg in various configurations, a hand, a forearm. Most of the kid had survived unscathed—from the torso up, that is. “I’m done entertaining your delusions,” he said shortly. “You’re on a timer. Your body is dead, but I’m keeping you alive here in my innate domain. Make a deal with me, and I’ll bring you back to life.”
Yuuji coughed, blood bubbling up from between his lips. “What…deal?”
“One: If I say a particular phrase, I gain complete control over your body for sixty seconds. Two: You will forget this conversation.”
“That sounds like a terrible deal,” Yuuji said weakly.
“In exchange for your life?” Sukuna asked, bemused.
“It’s yours too,” Yuuji bit back.
Sukuna smiled down at him. “I could so easily cripple you,” he said. “Leave you bound and broken at my feet for the rest of your pathetic life. You’re my soulmate, after all; why shouldn’t I do what I like with you?”
Standing above Yuuji, he filled Yuuji’s field of vision, blocking out most of the light. His face was cast in shadow, and only the gleam of his teeth, spread wide in a nasty smile, and his four glowing eyes could be seen.
Yuuji didn’t cry very much. He was strong, after all. He’d had to be, after his parents died and his grandpa got sick. He spent most of his time alone, friends few and far between and never particularly close. But he’d always hoped, somewhere in the back of his mind, that his soulmate would be different. That when he finally met the person who was his other half, they’d be kind and caring and accepting, and that for the first time in his life, he would be welcomed with open arms.
His eyes burned, and he couldn’t hold back the hot tears that escaped. His soulmate wasn’t even a person.
He never needed a storybook romance, but he had always imagined that his soulmate would at least be human—not a bloodthirsty, genocidal curse. Was it too much to ask for his soulmate to be capable of loving him back?
“Upset, are we?” Sukuna hummed, still gazing down at Yuuji. “Don’t cry, your face looks ugly like that.”
“Fuck you,” Yuuji spat.
Sukuna tilted his head back and sighed. “Watch your tongue, brat. Listen to me; I’ll amend our deal. A one-sided soulmate bond is unusual, but it’s not unheard of. I’m willing to take you on as an acolyte, if you afford me the proper respect. If you are able to gain a satisfactory level of skill, I’ll allow you to stay by my side when I begin the next great Age of Curses.”
“Why the hell would I want to help you subjugate humanity?” Yuuji said. “You’re crazy.”
“Don’t you want to know how to use my technique properly?” Sukuna asked.
“I know—how to use it,” Yuuji said, hacking out a wet cough in the middle of his sentence. “And there’s no such thing as a one-sided soulbond.”
Sukuna ground his heel down into Yuuji’s chest and watched him wheeze. “Maybe,” he said flatly. “You’ll never find out if you don’t accept this deal.”
Yuuji’s eyes flashed, and his hand flew up to grab Sukuna by the ankle. “You can’t hurt anyone while you’re in my body,” he said, his voice uncharacteristically serious. “And you teach me how to use the technique with no strings attached.”
“I teach you to use my technique in exchange for not hurting them,” Sukuna corrected. “Deal?”
Beyond Sukuna, the great arching ribs were beginning to turn fuzzy, white carapaces bleeding into red. Sukuna himself was turning blurry, his face occasionally obscured with bubbling black dots. “...Deal,” Yuuji croaked.
Sukuna’s foot eased off his chest, and Yuuji sucked in a rasping breath. “Stupid brat,” he heard Sukuna mutter, and then his eyes shut, and everything went dark.
—
Sukuna sat back on his throne, resting his chin on his fist. He could hear the brat being noisy as always, jostling his newly-healed lethal wound as he bounced around chattering to that blindfolded idiot and the school doctor.
Soulmates, huh.
From what he’d gathered, modern times treated finding your soulmate as the pinnacle of human interaction. Thousands of books and movies about simpering girls and hunky guys and something called “miscommunication” that the brat had assured him was the “best part of a chick flick,” whatever that meant. People even fell into predatory matching schemes just for the chance to meet their soulmate.
The whole thing was so contrived it made him sick. Soulmates weren’t about finding true love and riding off into the sunset. A good soulmate match was one where each person’s skills complemented the other, so that when they fought together in battle, there were no weaknesses. Soulmate teams were some of the most difficult opponents—their skills honed, so used to working together that communication was unnecessary. And they were vicious. If their partner’s life was in danger, a soulmate would do anything necessary to save them. A well-oiled, homicidal machine.
The brat just didn’t have what it took. His control of his cursed energy was poor and his finesse was nonexistent. It physically pained Sukuna to watch him mangle his cursed technique, and he didn’t even have a body.
It was interesting that he had the technique at all, though. Sukuna had been heavily skeptical of the brat’s claim that he had a secret technique, and his use of it against the special grade curse earlier had happened so quickly that he couldn’t study it. But it looked like his technique and it quacked like his technique, and that was simply not possible.
He’d brought his vessel into his innate domain in order to ascertain how, exactly, Yuuji was mimicking his technique. (If he happened to have a little respect beaten into him along the way, well, that’s just fine.)
Then Yuuji unleashed an inelegant but undeniable Dismantle, and Sukuna’s worldview had cracked down the middle.
Sukuna didn’t have a soulmate. He had been exceptionally gifted as a human, enough so to conclude that at least one of his many talents was from his soulmate. But he hadn’t been human for over a thousand years. If his soulmate ever did exist, they were buried long ago. Maybe he had even killed them himself.
Itadori Yuuji had crashed into his life with all the subtlety of an elephant. Sukuna’s first tantalizing glimmers of consciousness were tainted by his brainless, perky personality. The boy wouldn’t know tact if it bit him on the ass, he was loud, messy, uncouth…and he had been exorcizing curses, entirely self-taught, since the age of nine.
Sukuna resolutely refused to let himself be impressed. Every jujutsu sorcerer worth their salt had started as a kid, even if most of them at least had someone who would train them.
He hated to admit it, but Yuuji was strong, despite his poorly-controlled cursed energy and his butchering of Sukuna’s technique. If he trained the boy up, could he take his strength for his own? It’s clear that he believes in all that soulmate crap, buying into the romantic bullshit instead of the utilitarian truth. Sukuna can spin his web tightly, can bring Yuuji over to his side, and the brat won’t realize he’s been had until after Sukuna has dropped the heads of his friends and sensei directly into his lap.
In the physical world, the boy was still talking excitedly, babbling to the tired-looking woman as she fixed some sort of elastic band around his bicep. The thread of their binding vow settled firmly around Yuuji’s body, another drop of Sukuna’s cursed energy infusing with Yuuji’s own. He tugged on it, testing the give of their connection, and Yuuji stuttered, tripping over his own words before blabbing on again.
The boy would come back to him in time, their connection ensured it. Then Sukuna would break him, again and again, until he sucked every last drop of marrow out of his bones. Until Yuuji begged him to stop.
The connection between a vessel and its curse was far more sacred than a soulmate bond, after all. This body already knew his technique. When the time came, Sukuna would be able to crack it open and slither inside, filling Yuuji up with his own flesh.
Sukuna smiled to himself. Soulmates, really. The whole idea was ridiculous. Sukuna didn’t have a soulmate.
He did, however, have a new toy.