Cursed Spirit

A cursed spirit is composed wholly of cursed energy, leaving it metaphysical and beyond the sight or touch of ordinary people. Cursed non-sorcerers register only strange symptoms without sensing the spirit at fault, though anyone may glimpse a curse during a brush with death, when surging terror floods them with cursed energy. Grotesque in countless shapes and sizes, curses linger close to where they were born and reflexively prey on nearby humans. Holding an object steadies them most, some slip into inanimate things to become cursed corpses, and certain ones can brand a victim to chase them far from the origin point.

Their cleverness ranges broadly. The strongest tend toward upright, human-shaped builds, can hold genuine conversation, and organize into factions, yet wit is no monopoly of the elite, since even a grade 3 or 4 curse may reason. Hanami, for instance, bears a consciousness forged by humanity's long dread of forests, while Mahito springs from the loathing people aim at one another. Slain or stripped of a limb, a curse usually dissolves to dust in a disappearing reaction, and each one hides a core somewhere within its body.

Where curses and jujutsu began is mostly unknown, but because cursed energy rises from negative feeling, curses have almost surely accompanied humanity from the start. Modern Japan logs over ten thousand unexplained deaths and vanishings yearly as a direct result of their sway, all hidden from a public that cannot perceive them while sorcerers labor quietly to push the threat back. From 2017, the year the Hundred Demons held their Night Parade, curse-driven incidents turned both more common and more deadly, headlined by Sukuna's return and the abrupt rise of several unregistered special grade spirits inside Mahito's circle.

A curse forms when cursed energy seeps out of non-sorcerers carrying bad emotion, settling in one place like sediment until a spirit coalesces. Crowded sites such as schools and hospitals spawn them readily, thick as those places are with remembered fear and grief, and collective dread can raise a potent curse from something wholly unreal, like a famous monster, provided the masses keep pouring fear into the image. The most enduring fears, humanity's terror of plague and disaster among them, amass energy so vast the resulting spirit awakens with a consciousness bound to that fear.

Because jujutsu is the craft of steering the very energy curses are made of, they wield it by nature, unleashing a range of curse-related powers and cursed techniques peculiar to each spirit. The feeble rely on sheer presence and bodily weapons like fangs and claws, swarm on instinct in packs, and shrink from greater cursed energy, with passage through solid matter limited to low grades. The mighty hold colossal reserves and eerie techniques, and a number of special grades can even raise their own innate domains. In this era curses both outnumber and overpower sorcerers; against more than sixteen special grade spirits stand a mere four special grade sorcerers, and a pair of those scarcely commit to the fight, so without Gojo the curses would probably swamp Japan.

No conventional means harms a curse, since physical strikes do nothing whatever their force, and jujutsu's rule holds that only cursed energy exorcises a curse, a lethal cursed-energy hit wiping it out entirely. Half-human hybrids like the Death Painting Wombs fall outside that rule. Powerful curses mend themselves by reinforcing their forms with cursed energy rather than reverse cursed technique, which is actually fatal to most of them because positive energy corrupts the cursed energy they are built from. Any curse too strong to slay must be sealed by binding vow, much as Sukuna persisted as twenty sealed fingers. They also divide into known types: vengeful cursed spirits arising from cursed human deaths, imaginary vengeful spirits forged from mass fear of legend, and disease cursed spirits like the Smallpox Deity drawn from dread of plague.