machigatta ko wo mahou shoujo ni shite shimatta
Machigatta Ko wo Mahou Shoujo ni Shite Shimatta (I Messed Up and Made the Wrong Person Into a Magical Girl!), or Machimaho for short, is a manga by Souryu.
Before being published as a manga, Souryu uploaded a number of sketches and short comics to Pixiv. Those comics have served as storyboards for the manga. For example, the first manga chapter is mostly an expanded and polished version of the first Pixiv comic (pixiv #56701344).
Dead Sea Entertainment has licensed the manga for English release, with the first volume scheduled for release on 2018-10-09. [1]