Dogs

Dogs (狗-DOGS-, Ku -Dogs-) is a Japanese manga series by Shirow Miwa. The first manga of the series was published in 2001 as Dogs: Stray Dogs Howling in the Dark (Dogs: Prelude in the English version published by Viz Media). In 2005, a manga sequel began serialization in the manga magazine Ultra Jump as Dogs: Bullets & Carnage, continuing the storyline. The Dogs: Prelude manga volume has been adapted into a two-volume original video animation series (OVA) by David Production in 2009.

Plot
Sometime in the future, somewhere in Europe, a city has many levels of underground. Some of the levels contains secret dangerous levels that have answers to the past. Mihai is a retired assassin who has returned home to settle a vendetta and starts a new life as a restaurant owner. Haine was genetically experimented on as a child, which led to him possesing dog like attributes. Badou is his clumsy chain smoking partner who becomes deranged when denying cigarettes. Naoto was orphaned as a child and has amnesia. She is trained to wield the sword. Their pasts are somehow connected to the secret underground and the organization that controls it.