( discussing LORE ㅤㅤㅤㅤ ) it's easier to say what he didn't do in his life. but he carelessly destroyed numerous clans/fractions, erased bloodlines who were merely caught in the collateral damage. he was given quite a number of names despite not possessing one and wasn't from any notable lineage. so that must have been such a punch to the gut — being eradicated by someone who embodied jujutsu sorcery both physically and mentally, but again was from nothing. he was likened to a mythological creature, assumed by some as the epitome of strength. ( aka another title imaginary demon, as some didn't believe an entity with such prowess could exist and be human born )his entire life wasn't pillage and ruin, though it did occur on a whim to ease boredom. he was simply a force to be reckoned with, and unless you paraded around in his line of sight, he wouldn't bother making his presence known. to see him meant certain death, the weight of his cursed energy could no doubt be felt like an impending bolt from the sky coming to strike you down. but sorcerers that raised a challenge were anything but a common occurrence and sukuna didn't waste time on crushing insects. so he carved out a corner of his own, away from prying eyes. where no one could wander his path. just a presumed god living peacefully within nature, having built a home to coincide with uraume : the orphaned child whom willingly pledged their allegiance to him.soon enough would rumors arise, legends spoken, rare survivors speaking of their experiences. this bred devout cults to worship him. building shrines and raising monuments dedicated to their deity 𝐑𝐘𝐎𝐌𝐄𝐍 𝐒𝐔𝐊𝐔𝐍𝐀 ( 両面 ) : two-faced demon. becoming aware of this, he humored their groveling and even collected their sacrificial gifts with elusive glee. they were feeding him, admiring without expecting anything in return. it was amusing to him that people would willingly subjugate themselves to misery. at times, he would answer prayers to proceed his reputation. however everything loses its luster over time and they, along with all else, had become dull.kenjaku was introduced during his early adulthood. the closest thing to friendship he ever had. and only through a binding vow did he teach sukuna the delicate art of placing ones soul into cursed objects. in his remaining life cycle, he sorts every affair before the ceremony of sokushinbutsu is performed. once all 20 fingers were imbued with his energy and severed, uraume took possession of them thereafter. they placed them where kenjaku could recollect once preparations were settled. their contract seemed simple enough and he wasn’t necessarily privy to the finer details. ultimately, he needed a vessel to incubate his flesh and merge a sizable portion back together. that which would be vomited back out in what appeared as a malformed, premature fetus. ( thank you silent hill 3 for this idea, it's gross and infatuating ) this is placed into the abdominal jaw of his mummified corpse, a souvenir tengen had kept safe for prior centuries.in a disgusting way, yuji gave life to him. because he required someone that possessed the essence of his soul in order for this to be a viable rebirth. so sukuna ate himself, or poetically absorbed his twin again to become whole if you catch my drift. ( twins are viewed as the same person split into separate bodies ) thus why he doesn't rely on the use of vessels to manifest completely. itadori isn't needed further than that initial consumption of five digits, the first was given to him as a baby to set everything in motion. he is still searching for the remainder of his fingers and isn't at full strength until then. that’s where i coincide with canon events. i also follow either side when it comes to jin or wasuke being his twin reincarnated. because i know there is debate and confusion.BUT ... i will default to wasuke : 倭助 ( yuji’s grandfather ) being his brother due to their parallels and gege confirming sukuna was mistaken on his assumption that it was someone else. the failed attempt kenjaku made to seduce and conceive a child with him was passed to jin ( yuji’s father ) who deemed a far easier target for manipulation. be mindful that sukuna isn’t blood related to anyone on the canon spectrum. he died over a thousand years ago and sired no children. there’s a great disconnect from anyone claiming to be his kin and he will always disregard everyone attempting to relate with him on that front.