Responses
Someone already explain it. What Chainsaw erased is the concept. So as long as the concept is never an original like ear, fall, dkk, and it can be reinvented, it can exist again. For example. When u erase ear devil, ear is gone. Because uts original. But if u erase sword devil, u still have iron to make it. Someone can make it again, evetho they wont know what they make (at first).
The reason why nuclear weapons is reinvented as a concept is because atoms can still be split
first off, as ridiculous as it sounds, yoru's plan is such a great metaphor for humanity's never-ending bloodlust, chaos and violence.
second of all, if death is gone and the world is turned into chaos like death said, wouldn't there even be more devils? not to mention, is it even possible to use denji-chainsawman to erase death in the first place? nuclear weapons still got reinvented even after chainsawman ate it anyway :))