HAHA IT DOESNT EXIST YET and it’s super late in the series. It’s a crossover series about the Princes of Hell who are all ex-angels (except for Lust who was never celestial but dragged them all down to Hell by introducing the concept of SEX to the angels HAHAH very a la eve’s apple being a euphemism for sex) and Pride AKA Sukuna was the first to fall for it of course but an angel’s powers can’t be POOFED GONE so all his crew had their wings (their power) snipped and chained very Atlas very chained and bound to hold the mortal world up and THAT’S YUJI. Yuji is Sukuna’s wings and he’s stuck in Hell for the sole purpose of keeping his designated power afloat (he’s the Sun very Lucifer Morningstar, bringing the dawn) ANYWAY

In the crossover fic that introduces Sukuna to the canon (it’s a hxh fic and Illumi is the main character I’ve literally never written a fic centered around Illumi I think I was temporarily insane) Illumi is going to be Uraume in the exclusively JJK side of the fics so picture this all as Uraume: Uraume’s soul belongs to Sukuna who’s using them as leverage against Lust in this big revenge plot because Sukuna and Lust have had it OUT for each other for a while. Anyway Hell is kind of like a prison for Sukuna but it obeys Uraume because they’ve passed Sainthood trials by accident LMAO (came back from the dead, performed miracles, etc) and so Sukuna’s palace gives him access to Yuji and Yuji persuades Uraume to free him all “SUKUNA TRAPPED ME HERE WOE IS ME HELP ME I’m but an innocent little angel 😇 🥺” and so Uraume DOES and Yuji immediately goes POOF to NYC because Yuji’s known nothing of the world until reading Uraume’s mind and Uraume’s lived in NYC all their adult life ANYWAY-

So the rest of that existing fic is Uraume trying to find Yuji, being tricked into falling in love with Sukuna even tho Sukuna doesn’t give a shit, and then Sukuna ultimately sabotaging Uraume’s Sainthood so they’re stuck for eternity in Hell with no recourse for Heaven.

The book AFTER isn’t written but centers around Sukuna’s attempts to find Yuji and instead being summoned to a series of angels being LITERALLY KILLED IN RITUAL SACRIFICE in his name and the first is Megumi who Sukuna saves but Megumi’s wings are mutilated and he can’t leave Hell (where Sukuna dragged him of course) and Sukuna studies and experiments on Megumi under the guise of repairing his wings but really Sukuna wants to perform a transplant on himself (very Ten Shadows of him) but in the process an angel actually gets fully sacrificed and it’s the Angel of Gravity and everyone’s like “UHHHHH HELP THIS HAS NEVER HAPPENED BEFORE” and the Celestial Court appoints a Saint to ascend to Celestialhood or wuteva (Gojo) to assume the responsibility of Gravity and Sukuna’s the only person equipped to perform the transplant at which point Megumi (whose thought Sukuna has been helping him this whole time) learns that Sukuna was planning to transplant Megumi’s wings.