i'm sure this has been talked about before but personally i find it really fitting that sukuna's downfall was so ... lacking.
a lot of fans didn't like how sudden and somewhat anticlimactic that final battle with sukuna was, and as much as i have a feeling that it was because gege was rushed to end the series, i still find it very suiting that the way sukuna lost was one of the most pathetic ones in the series.
this is the guy who tried to make himself as inhuman as possible, who became the very "king of curses" that devoured countless humans to pass the time until his death and treated every life (even his own) as nothing more than a cog in a rigid system of strength, believing that to be strong you must be as selfish and cut off from everyone as possible.
yet he literally dies cupped tenderly in the hands of his worst enemy, a boy who believes that all life matters, no matter how ordinary or boring or weak a person might seem. there's no raging, burning, prolonged fight between them like there was between sukuna and gojo. and somehow, that says a whole lot more.
sukuna cared almost singularly about strength (he even said a hierarchy not based on it was a boring one). yet his own archenemy is yuuji, someone who is comparatively weaker than other sorcerers but is emotionally stronger than most of them... something sukuna doesn't put value in. yet it was yuuji's fierce empathy and merciful nature which made him want to reach out to even the heartless king of curses, and it was this exact quality of his which allowed him to connect with megumi, rip away sukuna from his friend's body, and finally win against sukuna.
it's also important to note that yuuji couldn't have won as he did without the help of his friends and allies, those who gave him strength, contradicting sukuna's notion that the strongest are strong because they do not reply on others.
and it's especially ironic considering how sukuna raged that he would destroy yuuji's ideals out of contempt that such a weakling could give him doubts about his own philosophy, yet it was yuuji and his beliefs that led to sukuna losing. and although sukuna didn't choose to return back to yuuji, we see that he had a last moment of reflection, before he died, in the form of acknowledging yuuji almost respectfully instead of only calling him brat. and in the afterlife, he seems so much softer and accepting of everything that happened. he lost. and he lost because of the brat whose ideals he couldn't break, yet they broke his.
sukuna, you were the strongest sorcerer in perhaps all of history, yet you were taken down by some chaotic, angst-ridden teenagers (of all things), one of whom you hated passionately for his ideals... but he was also the one to hold you as you died, who proved you weren't alone and that the monster you became was a matter of chance, the one who led you north and reminded you that you were human once, and that you can be again.
as underwhelming as the ending seemed, it was almost poetic and honestly very fitting for both sukuna and yuuji. gege, even under pressure you're still a mad genius. i can't believe i ever doubted this series.
