Basically Kenjaku put a curse into Kashimo but its not just any curse Its the Old King of Curses (i just had a idea if there was a actual Curse that was the king of them all (Spoilers: Since Sukuna was born and lived as a sorcerer who was the original King) and the only thing I can think of is making him a misfortune curse because with how everyone was dying and everything in the world its been unfortunate all of it
I did not make Jujutsu Kaisen all characters are Gege Akutami please go support them