Overall Skill Level: Back in the Golden Age of Jujutsu, the Heian Era, Ryomen Sukuna was feared and regarded with awe by all those in his time as the most powerful sorcerer of the age, defeating and killing thousands of jujutsu sorcerers even as they sharpened their skills against him. One of his feats included single-handedly slaughtering both the Sun, Moon, and Stars Squad and the Five Empty Generals, the most elite of the Fujiwara Clan's forces, leaving the authorities of Japan so utterly terrified that they were willing to hold festivities in his honor. The impact Sukuna left on history until he died earned him the title of the "Strongest Sorcerer in History", as well as the "King of Curses". His strength is still held in such a high regard that even Satoru Gojo, the strongest jujutsu sorcerer of the modern age, with arrogance levels of confidence and pride in his abilities, acknowledged his strength and that a fight between the two of them would be difficult.
More than living up to his titles, Sukuna possesses vast amounts of cursed energy and equally incredible control over it, with an extraordinary grasp over jujutsu, but he was also not reliant on jujutsu alone, possessing overwhelming physical prowess as well, capable of dispatching almost any opponent without unveiling his true cursed technique.
Even at his weakest state upon his incarnation in Yuji's body for most of the time he spent there, due to lacking most of his fingers, Sukuna remained extremely strong, capable of effortlessly dispatching powerful cursed spirits, including the likes of a cursed spirit who had ate his finger, which he easily retrieved from the cursed spirit after completely overpowering it. While purposefully weakening himself by removing Yuji's heart to ensure Yuji could not switch back with him, Sukuna utterly defeated Megumi Fushiguro, the inheritor of the Zenin Clan's prized Ten Shadows Technique and a prodigious genius who started school as a Grade 2 sorcerer with one of the highest potentials in Jujutsu High, to where Megumi admitted how utterly outmatched he was and was more than willing to unveil Mahoraga to defeat him. Sukuna would have killed Megumi had he not been interested in Megumi's unique talents, although before he could fight Megumi's trump card, Yuji managed to regain control of his body.
Sought out by Mahito's group under the belief that his revival could ensure their success, with just three fingers, Sukuna demonstrated an overwhelming superiority in power compared to Mahito by being able to resist his Idle Transfiguration completely and effortlessly inflict such a severe injury on Mahito when finally angered too much along with dispelling his Self-Embodiment of Perfection with a single attack. This terrified and intrigued Mahito to where he came to firmly believe that with Sukuna being on such a whole other level, his resurrection would surely bring about the Age of Curses.
Once Yuji's body had consumed fifteen fingers, Sukuna's overwhelming cursed energy was felt throughout Shibuya once he was awakened, compared to Satoru's own while being overwhelmingly more sinister. With 75% of his strength restored, Sukuna proved capable of overwhelming Jogo, the most powerful cursed spirit in Mahito's group, in a mostly one-sided battle as he easily overpowered the best efforts of his foe, leaving him utterly unable to even land the single hit that would get Sukuna to join him, before killing him with his own specialty of fire. His last act during the Shibuya Incident was to defeat Mahoraga single-handedly, a feat no user of the Ten Shadows Technique and even a member of the Gojo Family with the Six Eyes had done.
Incarnation (受じゅ肉にく Juniku): There is a slim chance that Sukuna will incarnate into whoever eats his fingers, gaining a physical, human body in the process. Upon Yuji consuming the first of his twenty fingers, Sukuna immediately came to possess his body, which he used to inhabit. Unlike other incarnated sorcerers, according to the Angel inhabiting Hana Kurusu, Sukuna, after experiencing death, had developed the knowledge to split his soul as cursed objects, which he demonstrated by imbuing all his cursed energy into Yuji's pinky finger and then force feeding Megumi with it to possess his body.
Master Hand-to-Hand Combatant: While immensely powerful as a jujutsu sorcerer, Sukuna is also shown to be an extremely skilled and powerful hand-to-hand combatant, using martial arts as his first method of combat before unleashing his jujutsu abilities. Sukuna can unite his cursed technique and his hand-to-hand prowess, making him an extremely difficult opponent to overwhelm in battle. During his fight with Megumi, he was able to effortlessly overwhelm Megumi in unarmed combat, countering his attacks in close-range with ease before delivering a strong punch that sent him flying. When Yuji attempted to attack him in his Innate Domain, Sukuna effortlessly countered all of Yuji's attacks before seeing through his attempt to trip him and defeating him with a single kick. With fifteen fingers, Sukuna easily overpowered Jogo with hand-to-hand combat alone before finally killing him with a single use of a cursed technique. He was later capable of fighting on par with both Yuji and Maki Zenin, both being exceptional unarmed fighters with extraordinary physical ability, deflecting most of their blows and landing a few hits on his own, using hand-to-hand combat.
Immense Strength: In his first appearance Sukuna has shown to possess immense physical strength despite being in an incomplete state. He could easily defeat a very large cursed spirit with just a simple swipe, and during his fight against Gojo he was able to punch the roof of the school so hard it causes the building to rupture and crack. He easily overpowered the likes of a finger bearer, a special-grade curse. When gambling Yuji's life against Megumi, Sukuna managed to fling the sorcerer through several building floors without effort and he easily overpowered and destroyed Megumi's shikigami. He even punched Megumi so hard, the raindrops in that area dispersed. With fifteen of his fingers, Sukuna punched Jogo through buildings and even destroyed the latter's jaw. His blows had considerable effect on Mahoraga. Upon taking over Megumi's body, he was able to easily pierce through Yuji's gut and send him flying across the city with a single punch, stunning him temporarily.
Immense Speed: Sukuna has repeatedly displayed overwhelming levels of raw physical speed, capable of effortlessly surprising most opponents with the sheer quickness of his movements. With three fingers, Sukuna easily slammed a finger bearer to the ground and even cut off his arm without him noticing. He was also able to effortlessly blitz Megumi several times, delivering powerful blows with Megumi barely able to react at all. With fifteen fingers, he easily overwhelmed Jogo and was able to keep up with Mahoraga in their fight. Sukuna was even able to appear in the middle of Atsuya Kusakabe and Panda, both capable sorcerers, with the former being a Grade 1 sorcerer.
Immense Reflexes: Sukuna can easily counter any opponent and is fast enough for his opponent to not even realize that their limb has been cut off. He consistently dodged Mahoraga's blows and countered during their fight. He was quickly able to put Mahoraga down for good before he had finished regenerating. He was able to dodge Jogo's Maximum: Meteor.
Immense Durability: Even in Yuji's body, Sukuna can use cursed energy to bolster his host's resilience. Sukuna was punched through five buildings and shown to be completely fine. Sukuna was able to survive a 200% Hollow Technique: Purple during his fight with Satoru Gojo.
Great Tactical Intellect: Sukuna is an extremely intelligent individual. He has fully grasped the nature of cursed techniques, curses and reverse cursed technique as a whole. Due to that, he is able to quickly deduce the inner workings of cursed techniques after only seeing them once or twice and creating suitable foils to such techniques. He did this against Mahoraga in their fight, and was able to defeat the shikigami after gaining an understanding of its technique. Sukuna was also able to realize the potential of Megumi's cursed technique just by seeing it once during their short battle and he was able to create a binding vow with Yuji in order to take Megumi's body patiently waiting for the right moment before executing his plan. During his fight with Hana Kurusu by using Megumi's memories he was able to make Hana think that Megumi is in control of his body and thus when she hugged him he was able to critically injure her.
Metamorphosis: Sukuna can create new eyes and mouths on his host, allowing him to see and speak without controlling the body of the host. For example, he made a single eye and fanged mouth on Yuji's left cheek to belittle and taunt him.
