Sukuna has long since been fascinated at the prospect of meeting his soulmate, regardless of whether they turned out to be his lover or his natural enemy.
His mark was an intricate pattern of lines and swirls, starting at the wrist of his left arm and traveling up to his shoulder. The color was a shimmering gold that glittered like diamonds in the light. It was a feature he proudly showed on constant display. A feature most people would fear.
Soul marks are indicators of how dangerous one’s soulmate is. A meter on the left arm, starting at the wrist and moving up depending on the danger level. If the design and color match, then you’re soulmates. And having a mark that goes all the way up to his shoulder meant that Sukuna’s soulmate was especially dangerous.
Sukuna eagerly looked forward to the day of meeting his soulmate, especially as he grew more powerful himself. He’d often wonder who was more dangerous, him or them? Where did he land on his soulmate’s arm? Would they band together or fight to the death? He wanted to know—needed to see that matching set of golden lines and feel that tug and pull of his soul to tell him what to do.
He never meets his soulmate, not for another thousand years until some fool eats his finger.
There’s a strange stirring in his soul that he chalks up to being incarnated, trapped inside another being like some parasitic prisoner. Itadori Yuuji, his unfortunate vessel, is somehow strong enough to contain and keep him suppressed. It’s certainly impressive, but it’s mostly just irritating.
At least his soul mark is still his own. Sukuna traces the gold lines, from wrist to elbow, lips curling up at the possibilities. His soulmate is alive, they’re out there somewhere. Otherwise, the gold would have faded away, the design on his arm would look like an interesting pattern of scars. But the gold on Sukuna’s arm shimmers, sparkling in the red light from the waters below.
Itadori wears long sleeves, keeping his soul mark hidden from sight. Sukuna tried taking little peeks in the beginning, mildly curious at how strong his vessel’s soulmate might be, but he quickly grew bored.
But with the brat standing in his domain, that curiosity sparks back up along with the stirring of his soul. He just wants to see, assess the level and promise to kill them if they aren’t already dead. He’s heard the death of your soulmate feels quite painful, even if you were enemies.
Sukuna grabs Itadori by the arm, ignoring the sharp gasp, and rips the sleeve off of his shirt. What he sees makes him pause.
An intricate pattern of shimmering gold, bold and thin lines that Sukuna always likened to strokes from a paint brush. It’s exactly the same as his own, traveling up from Itadori’s wrist to his shoulder. He should know, he’s studied his mark for years.
He runs his hand over Itadori’s mark, fingers tracing the lines, and Itadori jerks away. He felt it, Sukuna felt it too, his own arm burning.
Sukuna bristles, lips pulling back in a snarl as he watches the realization wash over his vessel and crush him. A quick flick of his fingers, he slices Itadori to ribbons and banishes him from his domain with a frustrated yell.
No, no, no!
That brat can’t be his soulmate! At least, not worthy of such a high level of danger. The kid can’t even touch him, let alone be a threat to his life. This must be a cruel joke, old gods laughing at him. He’s aware that potential is a factor, but even still. There’s simply no way.
The mark on his vessel’s arm makes sense, Sukuna is dangerous. But Sukuna’s mark, once a source of pride, now feels like a glaring sign of betrayal.
He huffs, leaning back in his throne, and runs his hand over the gold lines. The burn of meeting his soulmate has ebbed away, but he can feel his soul reaching out, that unconscious desire to intertwine itself with its perfect match now that he’s finally found them.
“Disgusting,” he spits.
Sukuna refuses to accept that brat as his soulmate, someone so weak and naïve. He glares at his mark, claws threatening to tear it to shreds. He feels lied to. He was promised a strong and dangerous partner, whether lover or enemy or whatever else they could have been. Instead, he was given a useless teenager who simply isn’t worth his time.
It’s not until Mahito that Sukuna realizes the true potential danger of his vessel. The pure, vile hatred that throws Sukuna back into his domain and unable to interact and reach any part of Itadori. He’s only a spectator now, and the sight is glorious.
“I will kill you.”
The words send a chill of delight running down his spine.
That cold, violent rage. That desire to destroy, maim, kill. Itadori is overflowing with anger and Sukuna is basking in it. Every hit his vessel throws out is brutal, verging on animalistic. Sukuna can’t get enough, lips curled in fascination.
Unfortunately, Itadori’s body gives out against his will. Too much blood loss, his vision going black. Sukuna would have healed him, desperate to see his vessel bloody his fists in the best of ways, but Itadori’s managed to block him out entirely for the time being. It’s impressive, and it leaves Sukuna reeling back in realization.
Should Itadori will it, Sukuna could be nothing more than a forgotten prisoner, trapped, never again to feel the light on his flesh. Should he desire it, he could strip Sukuna of his domain, chain him up, and lock him away forever.
Sukuna touches the mark on his arm, tracing the familiar lines up to his shoulder. Maybe that’s the danger here. The true danger of his soulmate. He grins, his soul trembling.
If he reaches his full potential, Itadori Yuuji could easily be worthy enough for Sukuna to fear and worship like a god.