Isekai Tensei de Kenja ni Natte Boukensha Seikatsu: "Mahou Kairyou" de Isekai Saikyou - Vol. 1 Ch. 3 - Borrowing A Grimoire

[MangaDex]

 

[nonexistent696969]

this magic reconstruction feels like coding

 

[ShinduPK4]

Bro casted rain and called it "fire extinguishing magic".

 

[Kshatria]

SO BIG!!!

 

[Otherworlder]

this magic reconstruction feels like coding

It reminds me of a story called The Magineer. It's explicitly this.

 

[Jstar338]

Bro casted rain and called it "fire extinguishing magic".

tf do you think a fire extinguisher in his world would've been?