Chainsaw Man chapter 196 recently came out and caused a frenzy because of the official introduction of the Death Devil, and also the return of the protagonist's impostor, which has been dubbed "Fakesaw Man" by the fandom. A lot of people have come up with theories regarding who he is, and a recent one suggests he is the amalgamation of Pochita corpses left behind.
This theory begins by stating that Pochita has left corpses of his Hero of Hell form throughout the entire Chainsaw Man manga, and the Fire Devil could have amalgamated said bodies with one of a human. It could be revealed that this Devil can merge the bodies of humans and these supernatural beings through the use of fire, serving as Denji's coming back to haunt him.
Disclaimer: This article contains spoilers for the series. Any opinion expressed in this piece belongs to the author.
Explaining how Fakesaw Man could be connected to Denji's past in Chainsaw Man

The first time that Pochita used his Hero of Hell form was during the tail end of the first part of the manga. As he was fighting Makima, his heart was thrown from space so he could survive, meaning that that version's corpse fell somewhere in pace. He later used it to distract Makima so Denji could strike her, meaning that this other body was also dropped somewhere.
When considering that the Fire Devil, disguised as the Justice Devil, managed to turn a lot of people into fake versions of the protagonist's hybrid forms, there is an argument to be made that they created Fakesaw Man. They could have used his fire abilities to connect the Pochita corpses with a human body, which is an amalgamation that can happen with the usage of this element in real life.
The idea of creating a fake version of the Hero of Hell makes sense, especially when considering that this Fakesaw Man seems to have two of the character's chainsaw mouths— which fits with this theory of using the two aforementioned corpses. Its lack of skin could also be a reflection of being burned off because of the friction when landing on the planet.
More details about this theory

The plot point of the fake Chainsaw Man has been looming for a long time, and author Tatsuki Fujimoto bringing it back in the same chapter that fully introduced the Death Devil cannot be a coincidence. There is a good chance that this being was created to do Denji's job of eliminating Death, or something along those lines, in case the protagonist didn't agree to do it.
On the other hand, the author has become known for throwing curve balls at his audience, and there is an argument to be made that this creature has a much more disturbing origin. It could have been created by accident and mirrors Denji's transformation, although its dialogue seems to suggest a degree of rationality.
Final thoughts
The fake Chainsaw Man is a plot point that has been under the surface for a long time, and it now seems that Fujimoto is going to deal with it. In that regard, the origin of this creature is going to define a lot of people's perceptions moving forward, about this entity and its role in the series.
Related articles:
- Chainsaw Man chapter 197: Release date and time, countdown, what to expect, and more
- Return of Asa's bully in Chainsaw Man chapter 196 proves one character's efforts fruitless
- Chainsaw Man chapter 196 teases a fan-favorite's return (& it's still not Power)
- Chainsaw Man chapter 196: Death Devil officially introduced as Fakesaw Man reappears