The Perfect Vessel (with a Catch): Kenjaku engineered Yuji to host the King of Curses, but apparently forgot to give him a strong immune system.Sukuna's Pure Annoyance: Ryomen Sukuna lives inside Yuji's soul and is utterly humiliated whenever Yuji gets sick. Sukuna's Reverse Cursed Technique can heal fatal stab wounds, but he refuses to waste his energy curing a runny nose out of spite. The Internal Feud: Sukuna is trapped in a domain filled with the sound of Yuji constantly sniffing and coughing, driving the King of Curses completely insane.Spiteful Refusal: Sukuna can easily neutralize poisons and heal severed limbs, but he flat-out refuses to clear Yuji’s nasal passages just to break his spirit.The Body Takeover: If Sukuna ever takes control while Yuji is sick, he instantly regrets it because his ultimate domain expansion gets ruined by a sudden coughing fit. Superhuman Strength: Yuji can run fast, jump high, and punch through concrete without any cursed energy.Black Flash: A high-level distortion in space that makes his punches hit with extreme power.Blood Manipulation: He learns to use lethal blood attacks from his half-brother Choso.Shrine Technique: He gains access to cutting attacks like Cleave and Dismantle.Reverse Cursed Technique: He learns to heal his own body from severe injuries

Stoic Nature: He is quiet, serious, and highly calculating.Moral Compass: He believes the world is unfair. He acts as a sorcerer to give kind people a better chance to live. Ten Shadows Technique: His inherited cursed technique lets him use shadows as a weapon and summon powerful creatures.Shikigami: He summons ten mythological spirits, including Divine Dogs, Nue, and the powerful Mahoraga.Domain Expansion: He can use an incomplete domain called Chimera Shadow Garden Stoic and Analytical: He is outwardly calm, quiet, and deeply tactical in fights.Strategic Shielding: In combat, Megumi would alter his tactical formations, using Shikigami like Max Elephant or Toad defensively to shield Yuuji from harsh environments, rain, or toxic cursed energy vapors.Environmental Alerts: Megumi would prioritize checking the weather and the physical layout of a mission area beforehand, packing extra umbrellas, warm layers, or changes of clothes for Yuuji in case of rain. If a mission involves cold or damp conditions that could trigger an illness, Megumi would advocate strongly to Gojo or the higher-ups to leave Yuuji behind at the school.

Straw Doll Technique: Her innate technique allows her to use a hammer, nails, and straw dolls to target an enemy's cursed energy or strike them via proxy from a mid-range distance.Resonance: A powerful ability where she drives a nail through a piece of her opponent (or a proxy connected to them) into a straw doll, directly damaging their soul from afar.Combat Style: Highly logical, calm under pressure, and possessing a high pain tolerance, allowing her to hold her own against powerful curses despite starting at a lower formal rank. She would constantly yell at him for not wearing a proper scarf, leaving his jacket unzipped, or tracking germs into the dorms.Dramatic Quarantine: Nobara would loudly banish him to his room the second he sneezes, declaring that his germ-ridden presence is a threat to her health and her shopping plans. Bodyguard Duty: If Yuji falls sick during a mission, Nobara's combat style would shift instantly, using her mid-range Straw Doll Technique to blast curses away before they can even get close to a weakened, feverish Yuji.

True PhysiologyHis perfected, original Heian Era form is over nine feet tall, featuring four arms, four eyes, and an extra mouth on his stomach. This unique anatomy allows him to continuously chant incantations and perform hand signs without exhausting his physical stamina.Insulting the VesselSukuna would constantly berate Yuji from within his innate domain, calling him a pathetic, fragile piece of garbage. He would find it utterly humiliating that a superhuman vessel can be brought down by a microscopic virus.Sensory TormentSince Sukuna shares Yuji's senses, he would be forced to experience Yuji's stuffed nose, sore throat, and pounding headaches. He would violently threaten to murder Yuji just to make the coughing stop.Terrifying WarningsIf Gojo or Shoko try to step in, Sukuna might manifest a mouth on Yuji's cheek just to bark orders at them, demanding they feed the vessel better food so the King of Curses doesn't have to deal with a running nose.Ruthless Domain ProtectionIf a curse tries to attack a feverish, bedridden Yuji, Sukuna would manifest instantly and obliterate the curse with a fraction of a second of Malevolent Shrine. His logic would be simple: "No one kills this brat but me, and certainly not while he is too dizzy to stand."Losing His CoolImagine Sukuna trying to give a terrifying, villainous speech, only to be interrupted by a massive, body-shaking sneeze. His majestic Heian-era dignity would instantly vanish.Innate Domain DisasterInside Yuji's mind, Sukuna's throne of skulls would be littered with used tissues. Instead of looking menacing, the King of Curses would be wrapped in a giant blanket, glaring death at Yuji while shivering.Having four arms just means Sukuna has more hands to hold ice packs to his forehead, massage his temples, and rub his sore eyes all at once.