Synopsis:
Eri Yukizaki is a girl who fights. She is a “pretty soldier.” Her foe is the evil Chainsaw-man, who doesn’t die even after being slashed. If he isn’t defeated, the world will have no future. I was wrapped into this battle, and my life has changed completely… A “non-stop” negative youth story!
Review:
When I first read this, I thought that it was a bit of a silly synopsis… Everything sounds generic… I was mistaken.
It appears that the manga is told in the perspective of the male protagonist of the story, Yousuke Yamamoto. In his perspective, it is like he is living a manga or anime by helping Eri Yukizaki defeat the Evil Chainsaw-man. It makes his life more exciting.
The Evil Chainsaw-man is, as his name suggests, an evil man, who wields a chainsaw. Eri has the ability to predict where he will appear and they do battle.
There are other underlying turmoils that the two main characters undergo, as they deal with losses in their lives.
It is a fun series to read, and it is also short. It may have only eight chapters, but others say that it was deeply portrayed and well written.
There are some "low" angles for the short-skirted Eri, so if you are bothered by them, then this might not be too good for you. 
Links:
onemanga.com
My Anime List
There is also a live adaptation of this series, in case you are interested, with an article here.
