Jujutsu Kaisen Universe
Conflict between sorcerers and curses, who haunt and bring harm to humanity, has spanned thousands of years. A society of sorcerers have organized themselves to work in the shadows to suppress curses and try to protect humanity. In the modern era, the Big Three Sorcerer Families and the jujutsu higher-ups control the landscape of the jujutsu world. Cursed Energy is a form of spiritual energy that leaks from humans as a result of their negative emotions, makes up the bodies of cursed spirits, and is utilized by sorcerers and cursed spirits alike to fuel their jujutsu. Cursed Spirits/Curses are a race of spiritual beings invisible to most humans. Humans who have enough cursed energy to manipulate it with cursed techniques are known as jujutsu sorcerers. Sorcerers who use their powers for evil are called Curse Users, while humans who cannot see curses or use jujutsu are called Non-Sorcerers. Strength of sorcerers and curses ranges from Grade Four (the weakest) to Grade One (the strongest), and Special Grade.
Chainsaw Man Universe
Japan in the 1990’s. Humans on Earth share the world with Devils from Hell who are created from humans’ fears - the more humans fear the object or concept, the stronger the Devil. Examples are: the Bat Devil, the Darkness Devil, and the Future Devil. Devils that are killed on Earth respawn in Hell, and return to Earth once they are killed in Hell. Devils can possess human corpses to become Fiends, which are usually identificable by their distinctly-shaped heads. Hybrids are humans with the ability to take the form of a Devil. In all countries, there are Devil Hunters - humans that often make contracts with Devils for certain powers and abilities. The humans often have to exchange things such as body parts, lifespan, etc. for these contracts. Private sector Devil Hunters are independently contracted, while Public Safety is a government organization, often taking more dangerous jobs. Tokyo Public Safety Special Division 4 is an experimental division that partners with Fiends, Hybrids, and human-friendly Devils.