Pochita

Pochita (ポチタ) is the Chainsaw Devil (チェンソーの悪魔, Chensō no akuma) who embodies the fear of chainsaws. He was the original Chainsaw Man (チェンソーマン, Chensō Man) prior to becoming Denji's heart.

Near-death State
After disappearing from his battle with the Four Horsemen and Weapon Devils, Pochita is reduced to a “near-death state”. In this state, he appears to be a small orange canine-like devil with a chainsaw-like appendage protruding from the centre of his head. Handles emerge from his body allowing him to be wielded like a chainsaw, and his short tail is in the shape of a chainsaw's pull cord.

Normal
His true devil form is of a large, humanoid devil with four arms and a chainsaw protruding from each, with another chainsaw coming from the front of his head, similar to Denji's hybrid form. An intestine still connected to his stomach is wrapped around his neck, resembling a scarf or a collar.

Hybrid
After making a contract with Denji, Pochita assimilates himself with him, fusing with his heart and becoming part of Denji's anatomy, thus creating a hybrid. This allows Denji to become Chainsaw Man by pulling the chainsaw cord in his chest. In this state, Pochita is smaller, has lost the chainsaw on his head, all his appendages, both handles and has blood vessels connected to him. Pochita however still retains his trademark cute canine face. Denji's chainsaw cord is also directly connected to the top of Pochita's head.

Personality
Unlike most devils Pochita communicated solely through barks and whines like an actual dog. However, after fusing with Denji, he is able to communicate with him in his mind. He continuously communicates with Denji through dreams, warning him to not 'open the door'.

Pochita deeply cared for Denji after his life was saved by the human, despite the devil's general hatred toward humankind. He willingly gave up his heart to Denji so that he could fulfill his dreams which Pochita loved hearing about.

Pochita exhibits a more erratic personality when in his true devil form, as shown when he quickly murders anyone who expressed even the slight bit of hostility towards him in the burger joint. However, he later tells Denji that he always dreamed of being hugged, but his strength made that impossible, implying that his murder spree at the burger joint was accidental due to him being unable to properly control his strength around others.

He also seems to answer the calls of help from humans and devils alike, proven when he saved both Makima and Kobeni from their problematic situations, though he later brutally assaulted the former after completing his task. Despite this, his love for Denji remained, as he was keen to fulfill his friend's dreams, and later even sacrificed himself to save Kobeni.

History
Much of Pochita's past is shrouded in mystery, with the little information available being provided by Makima and other devils. He was known as the Chainsaw Man in hell, and had the unique ability of erasing devils and their names by consuming them. Devils killed in this form couldn't reincarnate anymore, while the fear they represent was erased from existence, making Chainsaw Man a threat to devilkind and earning him the moniker of "The Devil that Devils fear the most" and "The Hero of Hell".

This infamy, however, made him the target of a vast number of devils, who killed him multiple times, despite which he always found a way to come back and fight again. His power was a subject of worship for some, making certain devils follow him, and the object of fear for others, who ran away trying to escape him. This eventually culminated in a battle between him, the Four Horsemen and the Weapon Devils in which he was badly wounded and, according to Makima, reduced to a "completely changed near death form", which is heavily implied to be his dog form. At the height of the battle, he vanished and somehow ended up on earth.

Pochita later finds Denji when the boy is mourning at his father's tombstone. At first, the devil seemed to react with hostility towards him, but he quickly fell to the ground, unable to endure his injuries any longer. In an act of empathy, Denji offered Pochita his blood so that he could recover from his wounds on the condition that the two would become partners. Pochita would live alongside Denji, assisting him in devil hunting and wood clearing while subsisting on whatever rations Denji could afford.

Intro arc
One day, both are mortally wounded by the Zombie Devil and his Yakuza-turned-zombies. Pochita then entered Denji's body, assuming the role of his heart, while repairing Denji's damaged or missing organs and body parts in the process. Pochita is last seen communicating with Denji internally, communicating his wish that Denji show him more of his dreams in exchange for being his heart.

Eternity Devil arc
Pochita's past as the Chainsaw Man is briefly alluded to when the 4th special division team is fighting the Eternity Devil. There, Denji notices that Eternity is mysteriously afraid of his chainsaws, and thus, is avoiding direct confrotation with him, asking for Denji's colleagues to kill the boy instead. The Devil also seems overjoyed by the fact that it would be the one to kill the Chainsaw Devil.

When Denji finally decides to face it head on, Eternity screams about how the Chainsaw Devil was still alive after all, and that Denji is far weaker than how Pochita was in the past. After Denji kills it, Himeno later ponders to Aki why the Eternity devil talked like he knew about Denji.

Bomb Girl arc
After Makima tells Denji that she will have to borrow Power for an blood extraction, she introduces him to Beam, a shark fiend obssessed with Denji's chainsaw's powers. Denji then asks Makima why Beam has such devotion to him, which she responds by saying that Denji ressembles someone, implied to be Pochita in the past. Later, when Reze and Typhoon are laying waste on the city, Angel realizes that Beam knows about the original Chainsaw Devil and asks him to spit out any information about on him to help Denji better understand his powers.

Beam then claims that the Chainsaw Devil of the past was very fast, but he moved without having to walk, as he used the chainsaw chains to hook into things to swing between structures. Denji misinterprets this information, using his chains to hook Beam and mount him instead.

International Assassins arc
Due to Reze and Denji's fight being caught on TV, various countries began sending assassins to Japan in order to prevent Makima from having the Chainsaw Devil's heart, forcing her to cancel her travel with Denji and putting him into a 24 hours watch. Dissappointed, Denji begins wondering who exactly Pochita is to begin with, and why everyone wanted his heart.

Gun Devil arc
Due to being unable to protect Denji and Power in Hell, Aki became distressed about the possibility of both of them dying in the upcoming operation to defeat the Gun Devil. Aki then asks Kishibe to quit the operation along with Denji and Power, surprising Kishibe, who expected Aki to be the one most eager for the event. However, Makima later persuades Aki to continue in the operation by forcing Denji and Power into staying with her.

Later, the Future Devil sends an ominous vision to Aki, stating that both him and Power will end up being slaughtered by Denji, and then the Devil that Devils fear the most will appear, foreshadowing Pochita's return in the future when Makima breaks his contract with Denji.

Control Devil arc
The Future Devil's prediction eventually comes true, Denji is forced to kill Aki and is unable to prevent Power's death by Makima. Left in a crippling depressive state, he asks Makima if it was all dream, unable to comprehend why she would do all of that. Makima then reveals that she wanted to bring Pochita back since the very beginning, however she was unable to do so because Pochita had to stay as Denji's heart due to the contract between them. Left with no other choice, she planned a way to break Denji's contract.

The terms of the contract stated that Pochita would remain as Denji's heart as long as Denji fulfilled his dreams of living a normal life. Thus, Makima made Denji live with Aki and Power in hopes that they would become like a family to Denji, and once that was done she would kill both of them to make Denji emotionally weak. Finally, she reveals that Denji killed his own father and gaslights him into believing that he was a horrible person because of his patricide and therefore did not deserve to live his dream of having a normal life. Denji agrees with her, and with that, Makima successfully breaks Denji's contract with Pochita, leaving the boy into an unresponsive state.

The day after, Makima walks alongside a catatonic Denji in a hallway filled with all of Tokyo's Special Division 4 Devils and Fiends. Makima then reveals that every single one of them were followers of the original Chainsaw Devil in hell, and that they were all waiting for his "ressurection". An unexpected explosion shows that Kishibe has brought in an entire division to kill Makima, with his agents then beginning to summon the Hell Devil to send her back to hell. However, she suddenly enlists the help of Chainsaw Man, forcing Pochita to take over Denji's catatonic body due to the broken contract, marking the fateful return of the original Chainsaw Man. Pochita quickly disposes of the Hell Devil, but the remaining agents revive it with blood and then it proceeds to cast Pochita back into hell. Soon after after arriving there, Pochita is greeted by hordes of devils that attack him. However they are no match for the original Chainsaw Man, as he quickly defeats them one by one effortlessly. Meanwhile, Makima reveals to Kishibe that Pochita is able to erase a devil's existence and the concept they represent by eating them, and that she's planning to fight him in order to defeat and control his power with the aim of erasing concepts that she deems unnecessary for humankind. Kishibe then asks her if she's not afraid of losing, which she responds by saying that she wouldn't mind being devoured by Pochita as she is a big fan of his.

Pochita somehow manages to find a way out of hell and returns to earth. Makima then reveals to Kishibe that Pochita will always aid those who ask for his help, but in return he will also kill them after the deed is done. Therefore, since she asked for his aid, Pochita is coming to murder her. She warns Kishibe to stay away and prepares to engage Pochita, but he kills her before she could even react. After briefly looking at Kishibe, Pochita hears Kobeni's call for help from far away and runs to her location, leaving Kishibe alone with Makima's remains.

Abilities
Being regarded as The Devil that Devils fear the most, The Chainsaw Devil is considered one the most powerful entities in the series after the Primordial Devils, being able to fend off hordes of devils in hell unscathed. The hunt for his heart alone was enough to cause an international conflict, and even Makima, the overall main antagonist of the series, considered herself inferior to him, needing the public's adoration to weaken and then defeat him.

Physical Abilities
Immense Speed: As noted by Beam, the Chainsaw Devil was renowned for his amazing speed. When fighting Makima and the hybrids, he efortlessly assaulted them before they could even react. He moves almost instantly, making it look like he's teleporting to his opponents.

Supernatural Abilities
Devil Erasure: Perhaps his most infamous ability, the Chainsaw Devil is able to consume other Devils, causing the fear they represent to vanish from public consciousness while also erasing their physical existence, shown by the fact that Kishibe didn't know about historical things like the holocaust, Nazis and even the nuclear bomb, meaning that the Chainsaw Devil at some point consumed their respective devils.

Revival: As a devil, the Chainsaw Devil should revive in hell after death. This makes him practically immortal.

Trivia

 * Pochita's ranking in the Popularity Polls are as follows;
 * Pochita ranked 9th in the First Popularity Poll, with 9,527 votes.
 * Pochita ranked 9th in the Second Popularity Poll, with 26,722 votes.
 * Pochita's dog form bears a heavy resemblance to the Makita brand of Chainsaws.
 * In fact, his name might be a play of Pochi (a common dog name in japan) and the suffix "Ta" (from Makita).
 * Pochita's true form was likely inspired by the Black Gauna from the manga series Abara, by Tsutomu Nihei. A series that Tatsuki Fujimoto said served as one of his inspirations for Chainsaw Man.