Hybrid

Hybrids, also referred to as a devil-human (real name unknown) are humans who can take on the form of a Devil.

Overview
In rare cases, a human can become fused with a devil and turn into a hybrid. The only known methods of becoming a hybrid are done via a contract and surgical transplants. Hybrids keep their human consciousness and appearance but can transform into human-devil hybrids through a trigger and manifest the supernatural abilities of their fused devils. The official name for hybrids was erased by the Chainsaw Devil, and hybrids continue to exist despite their erasure for unknown reasons. They are indistinguishable from regular humans, unlike fiends, while they are not transformed into devils.

Currently there are eight known hybrids: Chainsaw, Katana, Bomb, Crossbow, "Spear", "Flamethrower", "Longsword", and "Whip". Besides Chainsaw, the others are collectively named as Weapon Humans and were members of Special Division 5 under the supervision of Makima.

Hybrids usually remain in their human form when not transformed, but the Devil inside them can also turn back to their Devil form under special conditions, as seen when Pochita takes over Denji's body and fully transforms into the actual form of the Chainsaw Devil. The condition for this to happen is still unclear.

Whilst an explicit weakness or death of a hybrid has been shown so far, a conversation between Katana Man and Akane Sawatari that it involves the devil’s heart.

Abilities

 * Hybrid Transformation: The main ability of a hybrid is transformation into their respective devil forms fused with their human form. Certain actions act as triggers for hybrid transformation, with each action usually referencing a part of the devil a human is fused with (Ex. Denji transforms by pulling Pochita's tail like a Chainsaw start cord, Reze takes out a pin in her neck like a pin in a grenade). Their strength, speed, and durability are increased dramatically after the transformation and they also gain the ability of their respective Devil. Their transformation usually affects their heads and arms, but skilled hybrids can also transform their legs into weapons.


 * Blood Consumption: They are able to restore their health by consuming blood, like devils and fiends. However, their regenerative abilities are nigh-limitless and they can revive if there is an adequate amount of blood to consume, even if their head is severed or their heart is removed from their body. If there is not enough blood, the transformation will stop on the way even if they try to transform again, the armament will not appear even if you perform certain actions, or only the damage will recover and return to the human form. When transforming or disarming, the changed parts melt like mud.


 * Contract Creation: Like regular humans, and unlike fiends, hybrids can make contracts with devils, as it is shown that despite having a contract with Pochita, Denji is also able to contract with the Blood Devil. However, it is unknown if the devil inside the hybrids can make a contract with other humans.

Trivia

 * The term "hybrid" is a widely accepted placeholder name among fans but they are more accurately described as being fusions/merges between an already existing human and devil than a crossbred hybrid. While a hybrid doesn't necessarily have to refer to beings born through interbreeding means only, the term is most often used, in real life and in fiction, to refer to such. A devil and human hybrid is a term often used in other media to refer to the offspring born from a devil and human and not some transformation or fusion later in life, but there are exceptions.
 * In Chapter 103 a news reporter refers to the Chainsaw Man as a "devil-human" which sounds similar to one of the translations for the alternate translation for fiends "Devilman" or Devilmen. While this is one of the most "official" names in reference to the kind that we can get it still should not be taken as canon as the name is unrevealed and no one remembers it.
 * While all the hybrids currently seen are only weapon based, it is unknown if only weapon devils can become a hybrid or not.
 * Outside of Chainsaw, Katana, and Bomb, the majority of the hybrids don't have a fully canon name for their weapons, causing some inconsistencies in which to exactly name some of them (such as if the western sword is either Longsword or Broadsword). Until they get proper canonized names for their exact weapon types, they often get referred to what they can just be called visually.
 * Because Reze is a hybrid but is said to only contain one fragment of the Bomb Devil (with the rest of the fragments having unknown whereabouts), the entire Devil does not need to fuse with a human to make a hybrid.