Blue Sheep Reverie

Blue Sheep Reverie, also know as Aoi Hitsuji no Yume, is manga created by Makoto Tateno. There are currently 5 volumes with 4 being published in English by Juné.

In a city without a proper name protagonist Kai is in search for the killer of his lover, Maria. He suspects that Lahti, one of the "Four Kings" of the city, is the killer of Maria and gets close to him to carry out his revenge.

-- This manga contains:
 * Badass: The "Four Kings", and Kai.
 * Badass Grandma:
 * Badass in Distress
 * Genius Bruiser: Probably  since he seems to the most technologically inclined of the "Four Kings".
 * Homicide Machines
 * Professional Killer: What Lahti and  started as.
 * Rape As Backstory
 * Slipping a Mickey
 * Unlucky Childhood Friend
 * Professional Killer: What Lahti and  started as.
 * Rape As Backstory
 * Slipping a Mickey
 * Unlucky Childhood Friend