Sukuna

Appearance

Sukuna is a demon with four arms, two faces and a body covered in tattoos. He has four eyes, pink hair, and is usually seen wearing a light-colored kimono. He carried several spears with him in his prime.

Currently he's taken on an appearance similar to his host.

Power

Ryomen Sukuna is the undisputed King of Curses. The strongest type of curse is a Special Grade and there are three primary ways for a Curse to be registered as a Special Grade. While most Curses are birthed by large volumes of Cursed Energy in populated areas, Special Grade Curses (at least, of the ones we've seen) are anomalies insofar that they can only come about through: the acquisition of a Special Grade Cursed Object, a primal fear or emotion shared by all humanity such as Natural Disasters or hatred, or were a human that died and reincarnated as a Vengeful Spirit.

Since the amount of cursed energy directed towards a specific concept directly correlates with how powerful the resultant Curse would be, it's emphasized that the major villains of the series embody a specific principle. People's fear of natural disasters such as the earth and sea (earthquakes, volcanoes, tsunamis, fires) created intelligent and obscenely powerful Special Grade Curses like Hanami, Jogo and Dagon. Mahito is an overwhelmingly strong and uncannily humanoid Curse, who has the ability to challenge the fundamental concept of humanity, and test the limits and properties of the human soul since he was born from the hatred people share for one another.

Vengeful Spirits like Sukuna are mythological or urban myth/folktale in nature. Rika Orimoto was an innocent young girl tragically killed in an accident at the age of 11. She became a Vengeful Spirit when the boy she loved, Yuta Okkotsu, couldn't accept her death and cursed her. It was revealed that Yuta's ancestor was Michizane Sugawara, one of the Big Three Vengeful Spirits of the sorcerer families.

This may or may not come as a surprise, but Special Grade Vengeful Cursed Spirits are even stronger than the Natural Disasters. Jujutsu Sorcerers are the people who battle Curses. Suguru Geto was an evil former jujutsu sorcerer who could control thousands of Curses, including a plurality of Special Grade Curses. He waged war against the entire world of jujutsu sorcerers, and reckoned his chances of victory would go from less than 20% to 99% with Rika on his side. Rika is considered a surreal spirit of "endless" cursed energy, which, along with Geto's estimates of his chances of winning the war against all sorcerers, was immediately proven to be true. Geto, one of the four Special Grade Sorcerers, has a technique called Maximum Uzumaki where he combines the power of 4,461 Curses in his possession into a single entity and hits his opponent with all of their combined power. On top of that, he summoned one of only 16 existing Special Grade Cursed Spirits at the time, an Imaginary Vengeful Spirit, the Tamamono-Mae Incarnate. And yet he was singlehandedly defeated by Rika.

Not only did he barely escape with his life, he mused over the fact that he wouldn't have had to spend years collecting powerful Curses if only he had Rika. She is "a power that can change the world". Then there are Special Grade Cursed Objects. These are items with immense negative energy that can transform a being (either human or Curse) into a Special Grade level entity. Take for example the Cursed Womb: Death Paintings.

These are nine aborted fetuses that were the result of human experimentation at the hands of the most evil sorcerer in history. Cursed Objects are actual Curses bound to relics that can be incarnated into a host. Mahito was able to transform a human with absolutely zero potential or affinity for Cursed Energy usage into a morbid Special Grade with one of the Death Paintings.

As you can imagine, these are very dangerous objects that need to be sealed or locked away completely to avoid any and all exposure to the outside world. The potential for destruction and chaos they can reap when they fall into the wrong hands cannot be overstated. That's why highly dangerous Cursed Objects are protected in Jujutsu High's Buddhist Temple. The location of the building itself changes everyday, and the objects are kept in a storeroom that has over 1,000 doors—only one of which leads to them. And Tengen, an immortal sorcerer, is the only person who knows which one. Tengen is one of the pillars of the Jujutsu society. Kind of like a God who doesn't interfere with any any affairs but oversees all and protects sorcerers with his barriers.

The level of security gone into hiding these, and level of effort that goes into finding them is very important. The central MacGuffin driving the plot of Jujutsu Kaisen is the acquisition of 20 Special Grade Cursed Objects. These objects are the fingers of Ryomen Sukuna. Yes, his fingers (he has four arms).

A single one of Sukuna's fingers is so immensely powerful that Megumi Fushiguro mistook the residual energy lingering in it's empty container for an actual Special Grade Cursed Object. Which he was tracking for an entire day.

On top of that, unlike other Special Grade Cursed objects, Sukuna's fingers are the sole exception to Curses who can't cause any more damage once sealed as an object. His fingers can still do damage even after their lifestream has been halted and they've been sealed for millennia. Each finger still has enough energy to attract other Curses as a kind of beam or radar after over 1200 years.

Geto mentions above that Special Grade Cursed objects are indestructible. In Sukuna's case this actually relates to durability. Gojo explicitly tells Yuji that Sukuna's fingers can't be destroyed because he's just that powerful of a Curse. He even attacks it as a practical demonstration. What's more impressive is that Gojo's powers involve manipulating space at the atomic level. And he has techniques that involve outright deleting space.

So when he tells you that you can't destroy it, you best believe that you can't destroy it. He doubled down on this in the following chapter when he told Yuji a brief history of Sukuna. Sukuna defeated all Jujutsu Sorcerers during the Golden Age of Jujutsu, despite the fact that they actually sharpened their skills against him. After he eventually died, the rotting, decomposing flesh of Sukuna's corpse was still too durable to be destroyed by any Jujutsu Sorcerer, including Gojo himself as he practically demonstrated. On top of being completely invulnerable within his tier, Special Grade Curses are blessed with incredible regenerative powers.

There's no better baseline example of this than a Special Grade Curse who only became as such after it assimilated with one of Sukuna's fingers. This Curse (which can be referred to as the first Finger Bearer) was able to regenerate all four of it's limbs in a single panel after they were severed. Sukuna mocks it's capability stating that level of regen isn't hard for a Curse, implying Special Grades can casually complete much greater feats of regeneration. And this was after he expressed his disgust at the fact that the Finger Bearer and himself were both categorized as Special Grades in the first place. Since the Finger Bearer was a literal insect in comparison.

Sukuna at the time only had two fingers worth of power and the Finger Bearer had one. But the difference between them was like night and day, showcasing the exponential increase a single finger gives. As a matter of fact, Sukuna's fingers are used as a yardstick for power and fighting capability in the verse. The strength of multiple characters can be measured by their equivalent to a number of fingers. Jogo outright asks Geto how powerful would he be in terms of Sukuna fingers. A single one of Sukuna's fingers created the Finger Bearer, a Special Grade Cursed Spirit, which is a distinction for Curses that dictates a baseline of multi-city block busting power/durability. Sukuna with 2 fingers mutilated it and squashed it like a bug.

A couple times stronger than that and you get a Jogo, who is less than half of Sukuna's full power. Jogo can drop flaming, large building sized meteors from the sky which at reentry speeds would yield small city busting levels of energy[1]. Sukuna nearly kills Jogo for not bowing his head low enough in his presence.

Sukuna has never actually shown his full power. His latest appearance to date sees him wreaking havoc at 15 fingers, or 3/4ths of his power. That's a fraction that assumes the reunion of all the fingers doesn't result in the completed Sukuna being greater than the sum of it's parts. Which is most likely will be given the exponential increases in power that a finger adds. Jogo knew before engaging in battle with Sukuna how many fingers worth of power Sukuna had at the time (15) and how many fingers he was given to be worth (9 at most). But even he couldn't comprehend just how much greater the difference between them actually was.

Though Sukuna can be evidently seen playing with his food, he has no morals and has a natural thirst for blood. So he wouldn't hesitate to kill anyone who gets in his way in the quickest and most lethal manner possible. This is something his powerset and offensive techniques enable and compliment beautifully. The first time we see Sukuna, the very moment he incarnates, he rejoices over all the women and children "spawning like maggots" that he can finally get to slaughtering having been awoken. So he is merciless on top of being powerful.

Domain - Malevolent Shrine

Cursed Energy is a power source and Technique is what you do with it. A Domain is an area/environment created with Cursed Energy and physically manifested with Cursed Technique. An Innate Domain is what you call a Domain that's been created but hasn't been physically manifested with Technique. The technique that manifests a Domain is called Domain Expansion. Pretty simple right?

Domain Expansion is very powerful for 2 reasons: It massively amps the stats of the caster, and it makes every single attack they deploy automatically hit you no matter what. This is called the "guaranteed hit". Jogo, who outright said he'd lose to Sukuna in a battle of Domains, was able to bypass Gojo's Infinity which is a technique that brings an infinite series convergence into reality and makes it impossible for any physical attack to reach him.

Sukuna has potentially the strongest Domain shown so far. Malevolent Shrine differs from other Domains in that Sukuna doesn't need to create a separate space or environment using a barrier and his techniques can be applied directly. The ability to realize his Innate Domain without using a barrier as a medium is akin to an artist painting a masterpiece directly on air instead of a canvas.

Since most Domains are basically a pocket dimension, i.e a "separate space" where attacks are guaranteed to land, Sukuna's ability to attack directly from his Innate Domain without needing to expand the barrier (use a separate space as a medium) can be interpreted as directly attacking space itself. The painting on air analogy is very apt for this, as you'd be interacting with space directly if you painted on air instead of a medium such as a canvas.

Sukuna's Domain is the largest we have ever seen. He can expand it's range with a binding vow to create an area of annihilation with a radius of up to 200 meters.

Sukuna's Domain involves spamming Dismantle and Cleave, slashing things relentlessly without letting up until they're dead. Inside a Domain all attacks are fatal and none of them can be dodged or evaded. So Sukuna slices over and over, until his target turns into dust. His slashes are invisible, can not be seen or anticipated, can not be dodged, and they cut through the soul, so they can not be conventionally tanked or regenerated from.