Jujutsu Kaisen has done a great job at keeping up with MAPPA's record of amazing anime throughout the Fall and Winter 2021 anime seasons. The dark fantasy shōnenis unique, as its supernatural elements are based almost entirely on energy and curses through the use of which terrible feats can be achieved. So how exactly do curses work in Jujutsu Kaisen?
For the uninitiated, Jujutsu Kaisen follows Yuuji Itadori, an occult-loving student idly studying paranormal phenomena in his school's occult club – which comprises him and his two friends. When he's not with his friends, he visits his terminally ill grandfather who one day advises him to live in a way that'll permit him to die surrounded by loved ones.
Yuuji's grandfather dies shortly after and Yuuji is found in possession of a cursed item; a finger belonging to a demon known as Sukuna Ryoumen, or "King of Curses." Prompted by his grandfather's advice, Yuuji moves on to swallow the finger as the already uncontrollable curse would otherwise kill his friends.
The impact of consuming such a powerful curse should have killed Yuuji or rendered him beyond saving. Miraculously, he can control the curse and survive – although those who would prefer him dead are now many. Yuuji must learn to control his newfound powers and consume the other demon fingers to rid the world of many horrible curses. But even if he does that, many will still want him dead.
So what exactly are the curses in the universe of Jujutsu Kaisen and what does it mean to own a cursed object?
One of the first ideas to bear in mind about Jujutsu Kaisen is that, while it takes place in our own world, it makes it a fantastic setting. Jujutsu Kaisen operates on the principle that all living organisms give off energy called Cursed Energy, birthed by negative emotions such as rage and grief. This is not hazardous for everyone and mundane people can't see it.
Things however get tricky when an overflow of negative energy births Curses. This might be a bit hard to grasp. For brevity, it suffices to say that Cursed Energy, while created by negative emotions, isn't dangerous in its original form and people don't suffer ill effects by losing it. You can say that Cursed Energy is merely a symptom, while the Manifesting Curses are the disease.
The Curses are the real danger in the Jujutsu Kaisen universe, and they're often made worse by extreme feelings towards someone or something, for instance, the grief associated with natural disasters. This is where Jujutsu sorcerers come in.
The titular Jujutsu sorcerers whose ranks Yuuji has to join after consuming a cursed object are the only ones who can attempt to deal with a Curse – humans normally die if they try, which is why Yuuji is told to forget his friends once they come in contact with a Curse. His decision to help them by eating the finger is highly unorthodox and could have gone horribly wrong for him.
It's this decision, however, that allows him to become a Jujutsu sorcerer. Unlike normal humans who can't see the Cursed Energy within them, Jujutsu Sorcerers control their own Cursed Energy to reduce its flow, neutralize dangerous curses, or even perform Cursed Techniques – supernatural feats that vary from sorcerer to sorcerer.
Of course, the ability to be a Jujutsu Sorcerer isn't all about the gift of seeing curses. It's a road you can't come back from and it requires rigorous training, as Yuuji finds out. Possessing a cursed item with his body, and basically sharing a said body with a demon allows him to do many things other beginners could not.
As the story goes on, we find that there are even more things that can be done with curses. To creating one's own Cursed Objects to using the Reverse Cursed Technique – multiplying negative energy together to create positive energy. This is definitely confusing, but this is what makes Jujutsu Kaisen unique; its entire magical system is based on curses, meaning the characters can do with them things characters in other works cannot.
As for Sukuna, the "King of Curses," he is the most powerful sorcerer that ever existed, rather than an entirely otherworldly being. His Curse came when he died, and his fingers, preserved in grave wax are the most cursed objects imaginable in the universe.
The creators of Jujutsu Kaisen have given us an intricate, if a little scary magical system, quite different from any archetypical notion of a magical system. As the manga is still ongoing, suggesting a possible second season of the 24-episodeJujutsu Kaisen, we might see even more things that curses can do – or destroy.