whatjusthappend
some ideas: 1.You could create a version of sukuna just wanting peace, and maybe even form a life, you could also use the philosophy of him being human before and now a curse. 2.I recommend you get inspiration from the way you organize the texts, there are times when I don't know who is speaking, seriously, it's good to make it easier so you don't have any problems in the future. 3.Don't use the protagonist of your story as a support for the other protagonist, it's very cliché and will turn people away from your fanfic, I recommend you create an anti-hero who does whatever he wants. (Of course, that doesn't mean he needs to become Itadori's mortal enemy, it could be like an older brother teaching the cruelty of the world of jujutsy kaisen. All of this I wrote was using Google Translate, I follow the fics and barely comment, but you have a stone that just needs to be carved.