Spoiler free review, second edition.

Gwi is an awesome manga so it is with great pleasure that I give it an 8/10.

What is there to like about this manga you ask? Well, first of all the art style is strong and unique. It's simple in the sense that you can always tell exactly what is happening, but it maintains a certain roughness that greatly emphasizes the action. Perhaps the truest way i have to classify this art style is as "a type of art that is realistic in terms of human proportions, accenting only its fulcral design points to enhance the overall visual appeal".
The story is straightforward without being simplistic, and has just mystery to keep the reader guessing what will happen next. It's simple enough that you don't have to think outside of your reading session to fully understand it while being complex enough to keep you wanting more and to surprise you at the right moments. At times the build-up may seem long and hard to keep up with, but the delivery is worth the wait.
There are only a handful of main characters, which is understandable since this is a short manga. One thing I must denote is how well they are portrayed, each with their unique personality and goals that are easy to discern.
Lastly, this is a seinen manga with zero fanservice and none of the typical anime clichés we're used to. Being a fan of all types of action manga following sword wielding heroes, this was all I craved for, at the end of the day.

Conclusion: If you are looking for quick, short manga with plenty of badass swordsman action and an engaging story then you will find yourself at home reading Gwi. A sharp art style and well portrayed characters are all things you have to look forward to when reading it.