Fake Chainsaw Man

An individual (or individuals) referred to as Fake Chainsaw Man (偽チェンソーマン, Nise Chensōman) is a mysterious figure who appears multiple times in the Academy Saga. His real name remains unknown.

Appearance
He is an exceptionally tall male and has a rather bulky physique. He wears an all-black uniform and dark pants which appears to be the common outfit of male Devil Hunter Club members. He also wears a black cap which obscures his face, however his hair is still visible and was show to be black.

In his transformed state large chainsaws emerge from his forehead and arms; much longer than Denji's. Additionally as seen in the shadow, in his transformed state his head is also morphed into a demonic, mechanical shape with long, jagged fangs, similar to that of Denji's or Pochita's devilish forms, though lacking Denji's top handle and Pochita's horns.

Personality
Not much is known about his personality except that he speaks in a formal, polite, and calm manner. His actions so far hint at him wanting to help the real Chainsaw Man however he can. He also seems very knowledgeable about the Devils in Hell. He might be religious because he mentions Adam and Eve in his TV speech.

Justice Devil arc
After Yuko says her goodbyes to Asa, she sets off on a journey to find her Devil Hunter relative, seeking to find a way to return to a human form. She tried to get some rest on the rooftop of one of the buildings. He takes the opportunity to behead her in her sleep, presumably killing her.

Falling Devil arc
After Denji has been defeated by the Falling Devil, he approaches Denji and slashes his own hand to revive him with his blood. He exclaims he "still needs Chainsaw Man to fight"

Later as the Falling Devil blocks the way for Denji's and Asa's escape out of Hell, he appears behind her, tearing her apart and incapacitating her. He explains to Denji that the Falling Devil does not tolerate customers who don't finish their food, and as a result, the rest of the Devils in Hell will desperately try to devour Asa in order to satisfy her demands. He then asks Chainsaw Man to evade the other Devils until sunrise.

Current arc
He is later presented on live television by Haruka, to prove to the public that the Chainsaw Man Church really does have contact with Chainsaw Man. He introduces himself as Chainsaw Man and reveals who he is and why he fights. This greatly upsets Denji on the other side of the TV screen, furious about his backstory, achievements and motivations being falsified and misappropriated by someone.

Abilities
In general, he seems to be very powerful, as he has no qualms facing a member of the Primal Fears. Not much is known about the nature his abilities, however they are likely similar to those of Denji's Hybrid powers. These abilities include:

Devil Contracts
Unknown Devil Contract: He has a contract with a Devil unknown for an unknown price. He has claimed it to be the Justice Devil, which was later disproven. This contract appears to have given him the ability to transform into Chainsaw Man in some capacity.
 * Chainsaw Manifestation: Just like his original counterpart, he grows fully functional chainsaws from his arms and head. These chainsaws are extremely effective at cutting Devils' flesh as seen in when he ambushed the Falling Devil. It is unknown whether he can extend chainsaws from his legs like Denji can. Just like Denji he can also temporarily retract his chainsaws if he needs to do certain tasks, such as picking something up. Notably, retracting his chainsaws seems to leave long gashes in his arms unlike Denji's chainsaws, which simply melt away.

Physical Prowess

 * Enhanced Strength: He is shown to easily hold up Yuko's entire body with just one hand. Later after he incapacitated the Falling Devil he lifts her up as well, holding up her entire body weight with just his neck.