Forget the name , can anyone help?

[advan123]

(ANSWERED)can anyone help ,pls
the story is a guy isekai'ed ,timeskip(i forget :v)

he move to a town and then protect and build the town defences
,then he meet little dude who was mistaken for a girl by heroine.
this little dude can make a gun
,sorry my english is bad

 

[advan123]

no ,thanks
i already know the answer

 

[hazzack]

yo you left us hanging

 

[justforthelulz]

@advan123

 

[Variante]

I think he is talking about https://mangadex.org/title/30728/kuro-no-maou