WARNING: The following contains minor spoilers for the Jujutsu Kaisen manga.
Having swallowed the rotting finger of Sukuna, Jujutsu Kaisen's Yuji Itadori became a host for the King of Curses. However, it seems that even before then, Yuji was already naturally gifted when it comes to athletics and physical abilities. Being a sorcerer was never part of the original plan, but it looks like now he has to learn how to control the curse power that comes with being the host to the most powerful Curse in existence.
After swallowing Sukuna's finger, Yuji was taken to the Tokyo Metropolitan Magic Technical College in order to be exorcised, meaning that both he and Sukuna would die in the process. His death sentence has been suspended for the time being so that he can ingest the rest of Sukuna's rotting fingers ensuring there would be no chance for the Curse to return in another form. All of this just from joining the Occult Club to avoid signing up for the track team.
Yuji is a kind young man who values the lives of others and wants to help people, even if that means sacrificing himself in the process. So, what can Yuji, and his abnormal physiology, do to aid him in helping others?
Yuji Is A Fast Learner
It's said that the signs of a great learner are asking questions, dedication, patience, and being a hard worker. This is especially true in Yuji's case. He constantly asks his instructor questions to get a better understanding of what's going on around him and how to use his new curse power.
Not only this, but he seems to be naturally gifted when it comes to progressing, able to master new things in a short amount of time. He was the best at cooking among the First Years, and he was able to learn Satoru's Movie Appreciation Training quickly. Because he's a quick learner, he's also been able to master using the Slaughter Demon blade in a short amount of time as well.
Yuji is Very Proficient at Hand-to-Hand Combat
Yuji is highly skilled in the art of Taido Martial Arts and is able to perform several ancient techniques like the Knee Release, which he combines with Taido to perform a Manji Kick. The Knee Release removes the need for starting movements. Not only can he release his knees, but he can also release his hips and shoulders as well. Using the momentum from this release, he kicks his leg up and makes contact with his opponent's head.
Combining the Manji Kick with his Cursed Energy allows him to harm Cursed Spirits physically. Yuji is also able to make quick judgments and assess what kind of blow would be the most powerful. Yuji has great control over his body, as he is able to stop his punch just before making an impact, and he's able to adjust the power in his fist.
Even Before Sakuna, Yuji Had Superhuman Abilities
Even before becoming a Curse host, Yuji was physically gifted with increased strength, speed and durability. He was able to throw a lead ball and bend a soccer post and he could run 50 meters in just three seconds. It was this natural physical gift that allowed him to become a vessel for Sukuna without any ill effects in the first place, and mostly maintain control of his body in the process.
Since swallowing the finger, his gifts have only increased, as he was able to keep fighting after losing a hand and multiple fingers. He was also able to dodge attacks from opposing sorcerers from Kyoto with ease. Plus, when Sukuna does take control of his body, he is able to regenerate any parts of his body.
Yuji Has Great Control Over Cursed Energy
Despite only recently becoming a sorcerer, Yuji is able to control his Cursed Energy amazingly well. Thanks, in part, to his ability to quickly learn new things, he's been able to combine his martial arts with his energy to reinforce his attacks and hurt Curses. Having control also allows him to use techniques such as Black Flash.
This allows him to create spatial distortions when he impacts an opponent with a physical attack, then Cursed Energy a fraction of a second later, creating a flash of exponentially more powerful black energy. He can use these abilities up to four times before getting too worn out. With his Divergent Punch technique, Yuji punches a target, then uses his Cursed Energy to create a second impact, though he has since stopped using it due to the Kyoto third-years critiquing this attack.
Yuji is Resistant to Poison
Because he's a host to a Special Curse, Yuji is resistant to all kinds of poison. However, he is still susceptible to the pain that the poisons cause. This was first seen in his fight against Junpei where he proved to be immune to the Moon Dregs' poison.
Since there are 20 Sukuna fingers floating around -- due to him having four arms -- it seems that there is no current end in sight for the popular shonen series, so it will be interesting to see how Yuji learns to manipulate his Cursed Energy and learn new techniques. It also means that there are potentially other abilities that have yet to be awakened as a result of consuming Sukuna's finger. The more fingers he consumes, the more possibilities there are for new powers and abilities to emerge.
However, that does increase the possibility of Sukuna gaining control over Yuji's body. We've already seen Sukuna do just that during the Shibuya Incident Arc, so it's entirely possible that he will gain full control once all 20 have been consumed, which means Yuji will lose control completely. We'll just have to wait and see if Yuji and the others come up with a contingency plan for when that day comes.
