Chapter 0: Information on the World of Chainsaw Man

I understood that many people haven't read Chainsaw Man so I had the idea to make this auxiliary chapter to help them.

Don't worry, there will be no spoilers from my fanfiction but there will be information that can be considered spoilers for some Chainsaw Man fans.

Devils: Devils or demon are born in hell. All devils are born with a "NAME" that corresponds to a concept.

These can range from very tangible (dog, tomato, gun, etc.) to entirely abstract (future, past, space, curses).

Note that the concept does not necessarily need to refer to something that exists; since there is no indication that ghosts, zombies or angels exist in the world, yet all these names have corresponding devils.

Each name is unique to its respective Devil (so there cannot be two devils with the same name), although some overlap based on specificity is possible since there was both a War Devil and a World War II Devil.

Devils manifest according to the collective consciousness surrounding their names (for example: the Gun Devil appears to be constructed from firearms and has gun-related abilities).

They are the embodiment of the fear represented by the "NAME", so as long as this "NAME" arouses fear, they continue to reincarnate (in short, as long as humans are afraid of their name, they are immortal, lol).

Also keep in mind that the concept of the Devil itself does not necessarily have to be frightening in itself, but its power depends rather on the frightening image it has in the popular consciousness of humans.

For example, cars are not necessarily frightening in themselves, but Makima stated that a Car Devil would be powerful because of the fear of car accidents and other car-related incidents.

Another example would be the Blood Devil since most people do not fear blood itself, but they often fear the violent and horrible images of blood and the danger of bleeding.

(To put it simply, the more frightening the image conveyed by the devil's name, the more powerful the devil will be and conversely, the more harmless the image conveyed by the devil's name appears, the weaker the devil will be)

And do not forget that devils are immortal since demons who die in the human world reappear in Hell as long as their name continues to arouse some fear in humans.

So to permanently kill a devil, humanity must be able to completely forget it, as was the case with the Nuclear Bomb Devil in the Chainsaw Man world.

(Author's note: I really don't understand who's afraid of tomatoes, those who watched the anime or manga will understand me 🤣)

Physiology: The appearance and physiology of a Devil varies from one Devil to another, as its shape and bodily structure are often related to the "name" it embodies.

Devil Fragments: As demonstrated by the Gun Devil, Devils can be physically fragmented into several so-called pieces of flesh.

It is unknown how many Devils have undergone fragmentation. It is possible that Devil fragments are injured, destroyed, and become Demons unto themselves, but other parts of the main Devil remain alive and are not destroyed.

Presumably, a fragmented devil cannot be completely killed and start reincarnating until all of its pieces of flesh are destroyed or only their core.

Since the Gun Devil is the only example of extensive fragmentation and was more of a primal force than an intelligent being among the 20% observed, it is unknown if these pieces of flesh retain the personality of the original, each have distinct personalities, all lack distinct personalities, or if it varies from devil to devil.

If a fragment or part of a powerful Devil is consumed, whether Devil or human, they will gain more strength than before.

The possessed (or demons or Fiend , it depends on the version): are devils who possessed a corpse. Demons are considerably less powerful than their fellow devils and are able to use attenuated versions of their respective supernatural abilities. They can regenerate by drinking blood and gain strength from it, but unlike hybrids, they can die if mortally wounded. Some demons are able to temporarily transform into a devil. They are also unable to execute contracts unlike Devils and humans.

One example would be the Blood Devil known as Power.

Hybrid: have a human consciousness and appearance, but can transform into a devil-human hybrid and manifest the supernatural abilities of the merged devil.

The official name of hybrids was erased by the Chainsaw Devil, but hybrids continue to exist despite their erasure for unknown reasons.

Hybrids are able to transform into their hybrid forms via a bodily trigger. Their regenerative abilities are near limitless and they can come back to life if there is a sufficient amount of blood to consume.

According to Makima, this kind of Devil is very rare to see, even amongst themselves, and most people have only heard rumors of their existence, to the point that even Aki Hayakawa never thought they existed.

One example of a hybrid is the protagonist of the Chainsaw Man manga named Denji.

Devil transformation: are the result of contracts between humans and devils to acquire a devilish form. Unlike hybrids, they take on a much more monstrous form, cannot freely transform into humans, do not have the same triggers, and do not merge with the devil they contracted with.

The source of a demonic transformation can come from multiple devils. According to Yuko, it seems humans have turned into actual devils and need the aid of an outside source to turn back.

Racial ability of devil:

Fear Empowerment: All Devils are born with a "name" that ties them to a concept. Devils feed on the fear humans and other creatures have towards that concept and draw their strength from it.

For this reason, a devil's power is deeply linked to how humans perceive the concept and the visual imagery their "name" evokes.

The more fear is associated with a "name", the more powerful the Devil who possesses it becomes. One example given by Makima is how a Car Devil would be stronger than a Coffee Devil, since cars evoke the mental image of getting run over and dying, whereas coffee evokes no frightening ideas; Another example is the Chicken Devil, who is so weak he was kept as a pet at a high school and killed when a student fell on him.

Devils can also feed on the fear other devils have towards them, the Chainsaw Devil managing to become extremely strong by using other devils' fear as a power source.

Blood consumption: All devils can consume the blood of other creatures to heal their injuries, it is also implied that devils can become more powerful by consuming blood.

While all devils can consume blood to quickly regenerate, powerful devils have been shown to possess superior regeneration. Hybrids and other powerful devils like the Gun Devil and Darkness Devil have very potent healing factors.

The flesh or blood of a devil can be given to other creatures, making them stronger and even giving them the ability of the devil they ate, but this only works if the flesh/blood they ate came from a devil still alive.

One example is Power becoming more powerful after eating too many zombies or Denji fighting for a week against the Eternity Devil.

Contract creation: All Devils can make contracts with humans, allowing humans to borrow some of their power in exchange for a sacrifice. However, Fiends are unable to execute contracts and Devils are unable to execute contracts between each other (there is just one exception which is Makima the Control Devil).

Possession of corpses: All devils can also possess human corpses. In most cases, this ends up creating a fiend (as was the case with Power), although in rare cases, it can end up creating a hybrid under certain circumstances.

The devil's personality may reflect that of the corpse if the brain is still intact, as evidenced by the polite, gentle demeanor of the Violence Devil. In these scenarios, the Devil may also retain some memories from the body it took hold of.

In rare cases, devils deliberately wish to retain the possessed corpse's personality, effectively bringing them back to life, and resume their own personality from time to time. The only known example of this is the War Devil who took control of the young Asa Mikasa's body while keeping her ego intact.

Hybrid racial ability:

- Hybrid transformation: A hybrid's main ability is transforming into their respective merged devilish form fused with their human shape. Certain actions act as hybrid transformation triggers, each action usually referring to a part of the Devil a human is merged with (e.g. Denji transforms by pulling Pochita's tail cord like a chainsaw starter cord, Reze pushes a pin into his neck like a grenade pin). Their strength, speed and durability are considerably increased after transforming, and they also gain the abilities of their respective devil. Their transformation usually affects their head and arms, but experienced hybrids can also transform their legs into weapons.

- Immortality: Although hybrids can regenerate by drinking blood just like devils and fiends, they are also able to regenerate and even recover from fatal injuries by triggering their trigger without needing to drink blood. Examples of this ability include when Denji bisected Katana Man but the halves reattached when Denji triggered Katana Man's trigger by removing his left hand, or the many times Denji was revived by pulling his cord. This makes hybrids immortal, as unlike devils and fiends who go to hell upon death, hybrids will remain on earth for a seemingly unlimited duration. This is illustrated by Makima bringing back Reze and Quanxi long after their apparent deaths. Hybrids do not age either, as Quanxi, despite being at least as old as Kishibe, still has the same appearance after several decades, while the Whip Hybrid also claims to be around 82 years old.

- Blood consumption: They are able to restore their health by consuming blood, like devils and fiends. Additionally, their regenerative abilities are unlimited and they can come back to life if there is a sufficient amount of blood to consume, even if their head is severed or heart removed from their body. If there is not enough blood, the transformation will halt midway even if they attempt to transform again, the weaponry will not appear even if you perform certain actions, or only the damage will be recovered and revert back to human form. During transformation or disarming, the modified parts melt like mud.

- Partial immunity to abilities: Hybrids appear to be immune to certain Devil abilities, especially those that could forcibly transform them - this is seen by Denji being completely unaffected by the Zombie Devil's zombie transformation, Doll Devil's doll transformation, and (potentially) War Devil's weapon creation.

- Contract creation: Like ordinary humans, and unlike Fiends, hybrids can make contracts with devils, as it's shown that despite contracting with Pochita, Denji is also able to contract with the Blood Devil. However, it is unknown if the Devil inside Hybrids can make a contract with other humans.

Author's note: This is the essentials to easily understand the Chainsaw Man universe and I will regularly update this page.

I will also add HxH if I receive a similar statement with Chainsaw Man (people who have trouble properly appreciating the fanfic because they don't fully understand the universe).