I've seen debates about the naming of this manga. I feel its worth mentioning that Green refers to Irish and Blood to gangs (I'd assume).

Now onto the relatively short tale of revenge.

Story- 6

The story takes place in the USA, during the industrial revolution. Immigrants are flooding into the country which has led to the 6th District of New York, known as the Five Points being considered the worlds worst slum and is an area which is completely under the control and the law of various Irish gangs.

There isn't much room for development with it being short, add 40-50 more chapters and I'd probably be giving it an 8.

Character- 8

Only two characters get real development. I'm pretty sure the author planned on making it longer but reasons unknown he seemingly had to cut it short (axed?).

The two main characters are Brad and Luke Burns. Left by their Father (an infamous outlaw) 14 years prior to the story after he murdered their Mother they eventually found themselves taken in by the founder of the Grave Diggers (an Irish Gang) and now live in the Five Points.

Brad is an infamous hitman, who works for and was trained by the Grave Diggers and goes by the name 'Grim Reaper'. Brad uses a gunknife to carry out assassinations and is constantly searching for information about his Father.
There are only two things on his mind - Keeping Luke safe and getting revenge on the man who killed his Mother.

Luke works at the ports and is innocent, kind and hardworking - an anomaly in a world of corruption. He dreams of him and Brad owning land of their own and being free from the poverty they suffer. Luke is oblivious to his brothers line of work and ambition for revenge. He is basically the opposite of Brad but has significant development during the course of the Manga.

The relationship between the two is one of the highlights of the Manga but there isn't much depth to anyone else sadly.

Art- 9
Not much to say, it's similar to Attack on Titans art but much more detailed.

Overall- 8

Even though it was short it was enjoyable. If you are looking for a Western setting then you wouldn't go wrong checking this out. I just wish it was longer :(