In Jujutsu Kaisen, all living beings emanate a power source known as Cursed Energy (呪力, Juryoku), which arises from negative emotions that naturally flow throughout the body. Most people cannot control this energy, and as a result, continually release it. The accumulation of uncontrolled Cursed Energy gives rise to Curses (呪い, Noroi), malevolent spiritual entities driven to harm humanity. These Curses often manifest as grotesque monsters, drawing on traditional Japanese folklore, such as onryō (vengeful spirits), yūrei (ghosts), and yōkai.