Let me just start off and say that the story and concept behind this manga is amazing and should be a full anime series. Sadly, it's not popular enough to do so.
Dogs is split up into two different series: Stray Dogs Howling in the Dark and Dogs:Bullets and Carnage
The Stray Dogs series is animated, but the OAV ep is only 15 mins. There are 4 eps, each about one main protagonist in the series.
This series is actually the prequel to the mainstream series, so it would be ideal to watch the animated series or read the manga. It gives a little background behind the characters.
Now, the mainstream series is Dogs: Bullets and Carnage
This series goes into the main story, and also takes some info from the prequel.
I am hopeful for the main story to become a full, 24-26 ep series, because this series is truly amazing.
Dogs is set in a dystopian setting of a European city where violence, crime, genetic manipulation and other scientific brutalities have become common. The story focuses on four antihero protagonists who, through a series of coincidences, meet as they search for a way down to "the Below", looking for answers to their individual pasts.
Heine Rammsteiner, a science guinea pig
Badou Nails, a info broker who lost an eye
Naoto Fuyumine, a swordswomen with a nasty scar
Mihai (I forgot his last name) a former assasin