In Jujutsu Kaisen, Ryomen Sukuna is a cursed spirit and is considered the `King of Curses` because of his immense power.
It can be seen that Yuji Itadori’s life changed completely when he became Sukuna’s vessel.
Sukuna can save Itadori’s life
Sukuna once saved Itadori from complete death after ripping out his heart but did not abandon him.
Itadori has great power
As mentioned above, Sukuna is called the King of curses because of his unparalleled power.
Itadori can `weigh` every villain
We also know that Mahito is a thorn in the side of every Spellcaster, he manipulated and killed Junpei Yoshino for no reason, as well as almost killing Kento Nanami.
Itadori possesses enormous magical power
So far Sukuna’s power is immeasurable, he has killed the strongest cursed souls, can regenerate body parts with ease, and is essentially immortal.
Itadori can form a contract with Sukuna
So far, no one has explained why Sukuna was unable to fully control Itadori’s body, even though he had ingested a special level cursed item.