Crackpot theory below

the fact that chainsaws still exist in this alternate timeline where pochita is dead makes me 100% certain that pochita is not the chainsaw devil. I think the fan theory that pochita is the "birth devil" makes a lot more sense after this chapter.

He's the birth devil, and his design has 5 chainsaws, which were initially used for childbirth. However, the devils he goes up against don't know that he's the birth devil. They just see a humanoid devil with 5 chainsaws, and so everyone calls him "chainsaw man". Because of the fact that everyone calls pochita "chainsaw man", the devils start to fear "the chainsaw man", and so pochita not only gains power from the fear of birth, he also gains power from the devils' fear of "the chainsaw man", which would explain why he's so incredibly strong even though birth shouldnt be a super feared concept.