Devil in your heart: Deal with the Devil [Chainsaw man x OC fanfic]

Thirteen years ago, the world used guns as a countermeasure for devils. But some people abused this power. Leading people to fear, and increasingly, guns. This led to the birth of the Gun devil.

(this is a chainsaw man fanfic, this will be a lot different from the canon chainsaw man route. And I'm shit at fanfics. So don't try to kill me. Although I accept constructive criticisms. )

Ps. It's up for debate, but Chainsaw man is set in 1997 and I'm gonna set it like that in rhat time period.